Do something rare. Something that you enjoy doing (or think you would enjoy doing) that you don't do very often. Just getting out of the rut is a good (necessary) first step.

Hang out with cheerful people and let them rub off on you. (Uh...figuratively.) If they're one of those TOO-cheerful people, you may want to haul off and hit one of them. And then THAT will cheer you up, so you can't lose!

Go for walks often, by yourself or with others.

Drink plenty of water.

Stretch first thing in the morning, and before bed too, if possible.

Make a list of things you're grateful for (this one helps me get out of my "sad bastard" moments better than anything).

Observe & engage your senses. Devote at least 15 minutes each day (or as often as needed) to people-watch, animal-watch, experience nature. Look at the clouds or the stars. Listen to your surroundings. Smell the air.

Let your imagination do the work. Doodle/draw. Seeing something happy, even if just on paper, can help you feel like a big chunk of you is living in that happy, even for a small moment.

Just some ideas. If it's advice you're looking for, here's my best stuff: Listen to yourself. You can sometimes discover what naturally brings you happiness by doing what your most persistent, confident voice tells you it needs when all the other noise becomes just that -- noise. ♥

Make friends with people that have kittens!

I am not the girl to help you here. I will lurk and hopefully get some ideas for myself!