Habits form a core idea in behavior change. It requires that you change your behavior by regularly doing something. 
To get fit, you need to have a habit of eating well and exercising. To have loving relationships, you need good habits of communication.

Habits

Goal-setting is required to decide what you want and planning how to get there. Just having an idea of what you want to achieve is usually not enough. Setting a goal needs to be paired with plans, systems, or habits to make it achievable.
Goal-setting should be SMART (Specific, Measureable, Attainable, Relevant, and Time-bound.) However, some people argue for being completely process-oriented and ignoring outcomes.

Goal-Setting

Systems organize your behavior and decisions with formal rules. They are often built off of concepts of scientific management and organizational theory, but it is applied to your personal life. A productivity system is one type of system that is aimed at helping you get work done by organizing the things that need doing and telling you when to do them.

Systems

Much of self-improvement has to do with managing or listening to our emotions. Emotional self-regulation includes overcoming fears and anxieties or dealing with motivation and willpower even if they are separate from subjective feelings. The way you think about things affects how you feel, which affects what you do. How you feel affects your thoughts and actions. Your actions affect your feelings.

Emotional Self-Regulation

Learning is a synonym for studying. But it is also a basic psychological process: Every time we change from experience, we get better, we're learning. Learning is a core concept of self-improvement because it's how we understand the other tools better.

Learning

A core concept of self-improvement is considering the purposes themselves. 
<ul>
<li>It is considering what you ought to value in life. You might want to change some of your vices and enhance your virtues. You might decide happiness is the meaning of life or how you feel in the moment.</li>
<li>The second part is how you find meaning.</li>
</ul>

Values and Meaning

Thoughts are the things you say to yourself in your mind. It is an important part of the quality of life and as a way to achieve something. Thoughts can create emotional feelings.
Beliefs are sometimes classified as a propositional statement in your head. Others see it as a probability. Still, others might say beliefs don't really exist in our heads at all. Yet it is a central part of self-improvement.

Thoughts and Beliefs

<div>
In any field, there are a few ideas that are core to understanding everything else. Biology makes little sense without <a href="https://en.wikipedia.org/wiki/Natural_selection">evolution</a>. Physics without <a href="https://en.wikipedia.org/wiki/Symmetry_(physics)">symmetries</a> and <a href="https://en.wikipedia.org/wiki/Conservation_law">conservation laws</a> is baffling. All mathematics can be built out of <a href="https://en.wikipedia.org/wiki/Set_theory">sets</a>.
Self-improvement isn't usually regarded as an intellectual field. It's mostly an assortment of various gurus and pundits' suggestions on how you ought to be more successful, happier or wise. Thus it might seem like self-improvement doesn't really have core ideas at all-just opinions.
However, I think there are some common themes to the art of living better. These ideas are pervasive, coming up again and again. Even in the writing of people who take a stand against them, their prevalence still requires that they be acknowledged.
<h2>The Core Ideas</h2>
<h3>1. Habits</h3>
Nearly all forms of self-improvement first require that you change your behavior. Unless the improvement you're after is purely mental, you're going to have to actually do something first.
<figure><img src="https://www.scotthyoung.com/blog/wp-content/uploads/2020/03/habits.png"></figure>
Habits, then, form a central idea in behavior change. Being able to make certain behaviors automatic (or at least, more automatic) is going to help tremendously with any change you might want to make. To get fit you need to have a habit of eating well and exercising. To get rich you need a habit of saving and investing. To have loving relationships you need good habits of communication.
Not only are habits central to self-improvement, but they're also one of the best studied aspects of psychology. We have countless studies showing how the impact of association, rewards, punishments and contextual cues will have impacts on behavior.
If you're looking to dive deeper into habits, I recommend:
<h3>2. Goal-Setting</h3>
How can you reach a destination if you don't first know what it is? Goal-setting not only involves deciding what you want, but also planning how you should get there. It's a common theme, even if many people disagree about which aspects are most important.
<figure><img src="https://www.scotthyoung.com/blog/wp-content/uploads/2020/03/goals.png"></figure>
Goal-setting has also been studied by psychological research and generally found <a href="https://psycnet.apa.org/record/1981-27276-001">to be helpful</a>. However, it also seems clear that just having the idea of what you want to achieve usually isn't enough (although it may be a necessary start). Thus, goal-setting on its own needs to be paired with plans, systems or habits if it is going to be successful.
A good heuristic for goal-setting is that they should be <a href="https://en.wikipedia.org/wiki/SMART_criteria">SMART</a> (specific, measureable, attainable, relevant and time-bound). Implementation intentions, formulated as IF... THEN... plans <a href="https://www.sciencedirect.com/science/article/pii/S0065260106380021">tend to work better</a> than just focusing on an outcome on its own. <a href="https://en.wikipedia.org/wiki/Planning_fallacy">Planning fallacies</a> also need to be watched for as many goal-setting efforts can be overly optimistic.
Some view the disadvantages of explicit goal-setting to outweigh the benefits. These people either argue for being entirely process oriented and ignoring outcomes, or simply negate the value of achievement itself in favor of different values. 
If you're looking to dive deeper into goal-setting, I recommend:
<h3>3. Systems</h3>
Systems are tools that structure your behavior and decision with formal rules. A productivity system is one type of system-in this case aimed at helping you get work done by organizing the things that need doing and telling you when to do them. Other systems exist for helping make decisions, managing knowledge or organizing your approach to specific domains of life.
<figure><img src="https://www.scotthyoung.com/blog/wp-content/uploads/2020/03/systems.png"></figure>
The opposite of systems is an intuition-based or informal approach. What systems often encourage is creating explicit rules or guidelines which will discourage some tendencies you'd like to avoid. Getting Things Done, for instance, is a famous productivity system based on avoiding the tendency to forget what you need to do. 
Systems are often built off of concepts of <a href="https://en.wikipedia.org/wiki/Scientific_management">scientific management</a> and organizational theory, but applied to one's personal life. Thus business concepts like standard operating procedures, quarterly reviews and key performance indicators get repurposed as self-improvement concepts.
Systems, like goal-setting, also have detractors. Spontaneous, intuitive, creative or emotional approaches to improvement may be suppressed in an overly rigid system. Nonetheless, understanding systems, even if you choose to apply them selectively, is a core concept worth knowing.
If you're looking to dive deeper into systems, I recommend:
<h3>4. Emotional Self-Regulation</h3>
Much of self-improvement has to deal with managing, guiding or listening to our emotions. Indeed, those who take happiness to be an emotional state, central to our existence, may argue that all self-improvement ultimately is aimed at making us feel better.
<figure><img src="https://www.scotthyoung.com/blog/wp-content/uploads/2020/03/emotions.png"></figure>
Beyond being an end in itself, emotional self-regulation has many important instrumental purposes. Overcoming fears and anxieties represent a huge swath of self-improvement literature. Motivation and willpower overlap here as well, even if they may be better seen as concepts distinct from emotions or subjective feelings.
<a href="https://en.wikipedia.org/wiki/Cognitive_behavioral_therapy">Cognitive behavioral therapy</a>, sees thoughts, feelings and behavior as all being part of an interrelated system. The way you think about things affects how you feel, which affects what you do. How you feel, in turn, affects your thoughts and actions. Actions too, with their consequences can impact later feelings (exposure therapy is a clear example of this direction).
Others argue in favor of listening to emotions more than trying to manage them. In this view, emotions are important signals to tell you about the significance of events, often surpassing your ability to analyze situations rationally. The job, school or relationship you feel bad about might not be good, even if you can't say why.
If you're looking to dive deeper into emotional self-regulation, I recommend:
<h3>5. Learning</h3>
Learning is a tricky concept here because there are actually two different senses of the word. The first is a synonym for studying. This is something that matters to students, certainly, but it may not be something that feels central to your life if you're no longer in school.
<figure><img src="https://www.scotthyoung.com/blog/wp-content/uploads/2020/03/learning.png"></figure>
On the other hand, learning is also a basic psychological process. Every time we change from experience, get better at anything or remember something, we're learning.
In this second sense, learning is a core concept of self-improvement. Like habits, learning has been studied in incredible detail, making it a rich source of research-driven insights into self-improvement. Some might argue that learning is the core of psychology itself.
I've spent more time writing about this core concept than anything else, in part because I feel it has often been neglected in self-improvement, perhaps because many people conflate it with studying. Learning in the first sense, of deliberate studying, is also an important tool simply because it's the means by which one can understand the other tools better, so I tend to give it priority even if other authors don't.
If you're looking to dive deeper into learning, I recommend:
<h3>6. Values and Meaning</h3>
Most of the core concepts I've discussed so far are instrumental, useful for reaching some purpose. However, a core concept of self-improvement is a reflection on those purposes themselves.
<figure><img src="https://www.scotthyoung.com/blog/wp-content/uploads/2020/03/values.png"></figure>
This typically moves away from psychology and more towards philosophy and religion. What you ought to value in life and how you derive meaning from things are deep questions which we've debated for millennia. Even self-improvement itself is a perspective, one for which some pundits argue explicitly against.
There are two levels that this issue can be approached. The first is to find a system of meaning or values that you want to self-consciously emulate. This could be Stoicism, Buddhism, Christianity or some kind of secular humanism. You might want to consciously inhibit some of your vices and enhance your virtues. You might decide that happiness is the meaning of life or that the purpose of our lives transcends how we feel in the moment.
The second level of this system is to investigate meaning itself. This is a more esoteric job of philosophers, and perhaps too abstract for many people who simply want an answer for how life is to be. But given the plurality of systems which often contradict, understanding meaning and values themselves can often help structure your decision of which to strengthen.
The variety of value systems expressed in the former is too broad to give recommendations, but for those looking to think more deeply about the issue of meaning itself I recommend:
<h3>7. Thoughts and Beliefs</h3>
Thoughts refer to the things you say to yourself in your head. Much mental content isn't verbal, but our ongoing self-narrative is an important part of both our quality of life and as an instrument to achieving things.
<figure><img src="https://www.scotthyoung.com/blog/wp-content/uploads/2020/03/beliefs.png"></figure>
What beliefs are precisely (and whether they actually exist) is less precise. Some would classify a belief as a propositional statement in your head, like a little bit of logic with TRUE or FALSE attached. Others would see beliefs as statements of probability (90% TRUE or 54% FALSE). Still others might argue that beliefs don't really exist in our head at all, but are only inferrable by our behavior. In this sense we act as if we had beliefs, but don't really have anything corresponding to probabilities or propositions inside our minds.
Regardless of the exact format of thoughts and beliefs, they form a core concept in self-improvement for multiple reasons.
The first is that beliefs and thoughts may become self-fulfilling prophecies. Many argue that since your thoughts and beliefs have a causal impact on your behavior, and thus your results, you may get into cycles of self-limiting beliefs that become true only because you believe in them.
Thoughts can also create emotional feelings as well, and thus we may want to control our thoughts even if we don't care so much about changing our external outcomes. The constant worrier may have a nagging voice in her head that says her success never counts.
The importance of thoughts and beliefs ranges depending on whom you ask. For some, beliefs have mystical powers that transcend a physically justifiable version of reality. To believe something is, in a certain sense, to literally make it true. Others reject the supernatural, but argue that beliefs still highly constrain our attention, making self-fulfilling prophecies frequent. On the opposite extreme are those that argue for a mostly passive role of beliefs, recording the world but not much changing outcomes. To those people, having true beliefs matters more than believing things to make them true. Regardless of where you sit in this spectrum, the content of our thoughts and beliefs is central to self-improvement.
If you want to go deeper into this topic, I recommend:
<h2>Which Core Concepts Did I Miss?</h2>
There certainly are other concepts in self-improvement I've skipped over here. Some ideas are important, but didn't seem as universal so I excluded them (compound growth, progressive training, metrics). If you have your own thoughts of core ideas that come up again and again in self-improvement, please share in the comments!
</div>

In any field, there are a few ideas that are core to understanding everything else. Biology makes little sense without evolution. Physics without symmetries and conservation laws is baffling. All mathematics can be built out of sets. Self-improvement isn't usually regarded as an intellectual field.

Self Improvement

In any field, there are a few ideas that are core to understanding everything else. Biology makes little sense without <a href="https://en.wikipedia.org/wiki/Natural_selection">evolution </a>. Physics without <a href="https://en.wikipedia.org/wiki/Symmetry_(physics)">symmetries </a>and <a href="https://en.wikipedia.org/wiki/Conservation_law">conservation laws </a>is baffling. All mathematics can be built out of <a href="https://en.wikipedia.org/wiki/Set_theory">sets </a>. Self-improvement isn't usually regarded as an intellectual field. It's mostly an assortment of various gurus and pundits' suggestions on how you ought to be more successful, happier or wise. Thus it might seem like self-improvement doesn't really have core ideas at all-just opinions.

However, I think there are some common themes to the art of living better. These ideas are pervasive, coming up again and again. Even in the writing of people who take a stand against them, their prevalence still requires that they be acknowledged. Nearly all forms of self-improvement first require that you change your behavior. Unless the improvement you're after is purely mental, you're going to have to actually do something first.

Habits, then, form a central idea in behavior change. Being able to make certain behaviors automatic (or at least, more automatic) is going to help tremendously with any change you might want to make. To get fit you need to have a habit of eating well and exercising. To get rich you need a habit of saving and investing. To have loving relationships you need good habits of communication.

Not only are habits central to self-improvement, but they're also one of the best studied aspects of psychology. We have countless studies showing how the impact of association, rewards, punishments and contextual cues will have impacts on behavior. If you're looking to dive deeper into habits, I recommend: How can you reach a destination if you don't first know what it is? Goal-setting not only involves deciding what you want, but also planning how you should get there. It's a common theme, even if many people disagree about which aspects are most important.

Goal-setting has also been studied by psychological research and generally found <a href="https://psycnet.apa.org/record/1981-27276-001">to be helpful </a>. However, it also seems clear that just having the idea of what you want to achieve usually isn't enough (although it may be a necessary start). Thus, goal-setting on its own needs to be paired with plans, systems or habits if it is going to be successful.

A good heuristic for goal-setting is that they should be <a href="https://en.wikipedia.org/wiki/SMART_criteria">SMART </a>(specific, measureable, attainable, relevant and time-bound). Implementation intentions, formulated as IF... THEN... plans <a href="https://www.sciencedirect.com/science/article/pii/S0065260106380021">tend to work better </a>than just focusing on an outcome on its own. <a href="https://en.wikipedia.org/wiki/Planning_fallacy">Planning fallacies </a>also need to be watched for as many goal-setting efforts can be overly optimistic.

Some view the disadvantages of explicit goal-setting to outweigh the benefits. These people either argue for being entirely process oriented and ignoring outcomes, or simply negate the value of achievement itself in favor of different values. If you're looking to dive deeper into goal-setting, I recommend: Systems are tools that structure your behavior and decision with formal rules. A productivity system is one type of system-in this case aimed at helping you get work done by organizing the things that need doing and telling you when to do them. Other systems exist for helping make decisions, managing knowledge or organizing your approach to specific domains of life.

The opposite of systems is an intuition-based or informal approach. What systems often encourage is creating explicit rules or guidelines which will discourage some tendencies you'd like to avoid. Getting Things Done , for instance, is a famous productivity system based on avoiding the tendency to forget what you need to do.

Systems are often built off of concepts of <a href="https://en.wikipedia.org/wiki/Scientific_management">scientific management </a>and organizational theory, but applied to one's personal life. Thus business concepts like standard operating procedures, quarterly reviews and key performance indicators get repurposed as self-improvement concepts.

Systems, like goal-setting, also have detractors. Spontaneous, intuitive, creative or emotional approaches to improvement may be suppressed in an overly rigid system. Nonetheless, understanding systems, even if you choose to apply them selectively, is a core concept worth knowing.

If you're looking to dive deeper into systems, I recommend: Much of self-improvement has to deal with managing, guiding or listening to our emotions. Indeed, those who take happiness to be an emotional state, central to our existence, may argue that all self-improvement ultimately is aimed at making us feel better.

Beyond being an end in itself, emotional self-regulation has many important instrumental purposes. Overcoming fears and anxieties represent a huge swath of self-improvement literature. Motivation and willpower overlap here as well, even if they may be better seen as concepts distinct from emotions or subjective feelings.

<a href="https://en.wikipedia.org/wiki/Cognitive_behavioral_therapy">Cognitive behavioral therapy </a>, sees thoughts, feelings and behavior as all being part of an interrelated system. The way you think about things affects how you feel, which affects what you do. How you feel, in turn, affects your thoughts and actions. Actions too, with their consequences can impact later feelings (exposure therapy is a clear example of this direction).

Others argue in favor of listening to emotions more than trying to manage them. In this view, emotions are important signals to tell you about the significance of events, often surpassing your ability to analyze situations rationally. The job, school or relationship you feel bad about might not be good, even if you can't say why.

If you're looking to dive deeper into emotional self-regulation, I recommend: Learning is a tricky concept here because there are actually two different senses of the word. The first is a synonym for studying . This is something that matters to students, certainly, but it may not be something that feels central to your life if you're no longer in school.

On the other hand, learning is also a basic psychological process. Every time we change from experience, get better at anything or remember something, we're learning. In this second sense, learning is a core concept of self-improvement. Like habits, learning has been studied in incredible detail, making it a rich source of research-driven insights into self-improvement. Some might argue that learning is the core of psychology itself. I've spent more time writing about this core concept than anything else, in part because I feel it has often been neglected in self-improvement, perhaps because many people conflate it with studying. Learning in the first sense, of deliberate studying, is also an important tool simply because it's the means by which one can understand the other tools better, so I tend to give it priority even if other authors don't.

If you're looking to dive deeper into learning, I recommend: Most of the core concepts I've discussed so far are instrumental, useful for reaching some purpose. However, a core concept of self-improvement is a reflection on those purposes themselves. This typically moves away from psychology and more towards philosophy and religion. What you ought to value in life and how you derive meaning from things are deep questions which we've debated for millennia. Even self-improvement itself is a perspective, one for which some pundits argue explicitly against.

There are two levels that this issue can be approached. The first is to find a system of meaning or values that you want to self-consciously emulate. This could be Stoicism, Buddhism, Christianity or some kind of secular humanism. You might want to consciously inhibit some of your vices and enhance your virtues. You might decide that happiness is the meaning of life or that the purpose of our lives transcends how we feel in the moment.

The second level of this system is to investigate meaning itself. This is a more esoteric job of philosophers, and perhaps too abstract for many people who simply want an answer for how life is to be. But given the plurality of systems which often contradict, understanding meaning and values themselves can often help structure your decision of which to strengthen.

The variety of value systems expressed in the former is too broad to give recommendations, but for those looking to think more deeply about the issue of meaning itself I recommend: Thoughts refer to the things you say to yourself in your head. Much mental content isn't verbal, but our ongoing self-narrative is an important part of both our quality of life and as an instrument to achieving things.

What beliefs are precisely (and whether they actually exist) is less precise. Some would classify a belief as a propositional statement in your head, like a little bit of logic with TRUE or FALSE attached. Others would see beliefs as statements of probability (90% TRUE or 54% FALSE). Still others might argue that beliefs don't really exist in our head at all, but are only inferrable by our behavior. In this sense we act as if we had beliefs, but don't really have anything corresponding to probabilities or propositions inside our minds.

Regardless of the exact format of thoughts and beliefs, they form a core concept in self-improvement for multiple reasons. The first is that beliefs and thoughts may become self-fulfilling prophecies. Many argue that since your thoughts and beliefs have a causal impact on your behavior, and thus your results, you may get into cycles of self-limiting beliefs that become true only because you believe in them.

Thoughts can also create emotional feelings as well, and thus we may want to control our thoughts even if we don't care so much about changing our external outcomes. The constant worrier may have a nagging voice in her head that says her success never counts. The importance of thoughts and beliefs ranges depending on whom you ask. For some, beliefs have mystical powers that transcend a physically justifiable version of reality. To believe something is, in a certain sense, to literally make it true. Others reject the supernatural, but argue that beliefs still highly constrain our attention, making self-fulfilling prophecies frequent. On the opposite extreme are those that argue for a mostly passive role of beliefs, recording the world but not much changing outcomes. To those people, having true beliefs matters more than believing things to make them true. Regardless of where you sit in this spectrum, the content of our thoughts and beliefs is central to self-improvement.

If you want to go deeper into this topic, I recommend: There certainly are other concepts in self-improvement I've skipped over here. Some ideas are important, but didn't seem as universal so I excluded them (compound growth, progressive training, metrics). If you have your own thoughts of core ideas that come up again and again in self-improvement, please share in the comments!

Bite-sized knowledge
to upgrade
your career

What are the Core Ideas of Self-Improvement? | Scott H Young

Habits

Goal-Setting

Systems

Emotional Self-Regulation

Learning

Values and Meaning

Thoughts and Beliefs

IDEAS ABOUT

MORE LIKE THIS

The Complete Guide to Self-Control | Scott H Young

The Value of Learning "Useless" Things | Scott H Young

The Complete Guide to Motivation | Scott H Young

It's time to

READ

LIKE

A PRO!

Bite-sized knowledgeto upgradeyour career

What are the Core Ideas of Self-Improvement? | Scott H Young

Habits

Goal-Setting

Systems

Emotional Self-Regulation

Learning

Values and Meaning

Thoughts and Beliefs

IDEAS ABOUT

MORE LIKE THIS

The Complete Guide to Self-Control | Scott H Young

The Value of Learning "Useless" Things | Scott H Young

The Complete Guide to Motivation | Scott H Young

It's time to

READ

LIKE

A PRO!

Bite-sized knowledge
to upgrade
your career