The purpose of logic is to arrive at the truth. There are two basic forms of truth:
<ul>
<li>Ontological truth - what exists in reality.</li>
<li>Logical truth - the truth of statements.</li>
</ul>
Logical truth is founded upon ontological truth.

Arriving at the Truth

Ideas should not be a product of pure subjectivism, but must always touch base with the facts in the objective world from which the ideas were born. (e.g., the idea of a "cat" should refer to an actual cat.)
This is much harder to do with more complex ideas, such as capitalism and socialism.

Match Ideas to Facts

Logic is about finding out if statements are true or false, and the ability to express ideas clearly.
<ul>
<li>Don’t assume your audience understands your meaning if you don’t make it obvious.</li>
<li>Speak in complete sentences.</li>
<li>Don’t treat opinions as if they were statements of objective fact.</li>
<li>Avoid double negatives.</li>
<li>Use language your audience will understand.</li>
</ul>

Communicating Effectively

Becoming a logical person involves cultivating intellectual habits and skills that may seem simple, but are only achieved after lots of education and training.

The logical person

Evasive language does not directly state what a speaker has in mind. It results in two problems: 
<ul>
<li>It can deceive the audience.</li>
<li>It can distort your listeners' sense of reality. </li>
</ul>
If we consistently use evasive language, we may eventually believe our own bad rhetoric.

Evasive Language

When we're not paying sufficient attention to a situation, it is easy to make mistakes in reasoning.
The logical person has to train himself to always pay attention, even in familiar situations.

Attentiveness

If the fact is an existing thing, then access it to establish its factualness.
If you cannot establish factualness by direct evidence, then test the authenticity and reliability of the indirect evidence.

Get the Facts Straight

We can only communicate our ideas if we use words that accurately express those ideas. Finding the right words could be difficult. In such a case, we should go back to the source of the idea to bring clarification.

Match Words to Ideas

Our ideas are the way our minds understand the objective world. Clear ideas consistently reflect that world, while vague ideas give a distorted view of the world.
The logical person is always testing his ideas for accuracy.

Clear Ideas

The logical person understands that his ideas are based on things that exist.
Many ideas may seem true at first, but when you spent time looking into the sources of those ideas, you'll find they originated in legends.

The Origins of Ideas

"Vague" and "ambiguous" originates from Latin words that mean "wandering."
A logical person avoids vague and ambiguous language. He doesn't use language that dances around ideas but uses precise vocabulary, so the listener knows exactly what he is talking about. If he refers to complex terms such as freedom or equality, he ensures to define his understanding of the word before proceeding.

Vague Language

Becoming a logical person is not just a matter of memorizing and applying formulas, or learning how to tell the difference between a valid and an invalid syllogism. Rather, it involves cultivating intellectual habits and skills that, though they may seem simple and obvious, are only achieved after years of struggle and education.
In his book Being Logical: A Guide to Good Thinking, venerable philosophy professor D.Q. McInerny lays out the following 10 habits that people must cultivate if they are to think clearly and effectively:

Clear Ideas

Similar ideas to Clear Ideas

The Origins of Ideas

Walking For Clear Mind

4 Principles for Effective & Clear Communication