According to research, showing gratitude boosted happiness by a noticeable level.

Writing thank-you notes, or just a nice letter, is an effective method of increasing happiness and life satisfaction.

Research has found that exercise is a proven strategy for feeling better, increasing your energy levels and reducing tension.

The release of endorphins has an addictive effect, and more exercise is needed to achieve the same level of euphoria over time.

Humility is not thinking less of yourself, but thinking of yourself less.  - CS Lewis

Self-esteem that is bound to external success can lead to small spurts of happiness but is not long lasting. Focus more on the betterment of yourself for the sake of those around you, rather than for your own ego.

"When people realise that their life is almost over and look back clearly on it, it is easy to see how many dreams have gone unfulfilled. Most people had not honoured even a half of their dreams and had to die knowing that it was due to choices they had made, or not made. Health brings a freedom very few realise, until they no longer have it."
 - A study on the Top 5 Regrets of the Dying

Research shows that feeling “rushed” is a one-way street to stress and unhappiness. Too much boredom can be burdensome. 

To find a balance, learn to say "no" to opportunities that do not excite you.

Researchers found that setting ambitious goals tends to make people happier.
Big goals are often an important element of getting people moving in the first place.

Small pleasures matter. Research has shown that you need to have small wins along the way in order to be truly happy. 

Experiences trump material purchases (in general) for the 5 following reasons:

1. Experiences improve over time while physical items can get old quickly.
2. People revisit experiences more often 
3. Experiences are more unique and can simply be enjoyed.
4. We adapt slowly to experiences because it takes our brain longer to get used to them while we are better able to adjust to material purchases.
5. Experiences are social.

Great minds discuss ideas; average minds discuss events; small minds discuss people. - Eleanor Roosevelt

Deep conversations are often those we reserve for close friends and family, which explains why close relationships are so important for our happiness.

Researchers found that although the process of becoming proficient at something took its toll on people in the form of stress, 

participants reported that these same activities made them feel happy and satisfied when they looked back on their day as a whole.