Remember everything that brings you big or small pleasure. The laughter of a loved one, traveling, playing with children, a glass of good champagne, a favorite of aquarium fish, socializing with friends, swimming on the back or a serving of chocolate ice cream? Try to surround yourself with these pleasures, or at least once a week to afford anything from them.
Try to do at least a few higher desires, which they say "dream life". Of course, to fly in space is unlikely, but, say, to see the real Northern lights is possible. Enough to fly in the winter in Murmansk (or any Northern city situated above the Arctic circle) and take the frosty clear night.
Often give gifts to loved ones. It will be nice not only to them but to you. Even if it will be cheap surprises, and even better, made things with their hands. To get even more pleasure from this process, present your favors for no reason. And always do it unselfishly.
Learn to forgive or at least forget the unpleasant situation. To live with a stone heart is very hard. Moreover, if you will constantly swarm the negative emotions, you will not be able to fully enjoy life. Do not waste it on resentment pursed lips very hard to smile.
From time to time change something in their appearance. Of course, it is not necessary to rush from one extreme to another, but you always can change your hairstyle or makeup. Or swap shirts a striped shirt in a cage.
Sing. Hum a favorite tune on the way home, washing dishes, in the shower, etc. Even if you have a bad mood, singing or a quiet purring under his breath clearly distract from evil thoughts.
Get more nature. The natural beauty of the planet, unspoiled by man, is fascinating. Admire the mountains and listen to the sound of the surf, and if this is not possible, try at least often, to walk among birches or NAP in a hammock outdoors.