Something that really helps me is doing things that are relatively difficult, but that I know I can do it. Nailing twenty consecutive free throws, running (or jogging) for 10 kilometers, beating a very difficult part of a videogame, cooking a very tricky but tasty dish... I don't know, it can be many things. Everyone should be able to find some for himself.
But as others have said, the best way to deal with low morale or depression is to hang out with your closest friends. They will understand you and will cheer you up. Heck, only by doing fun stuff with them you will feel better xD
The worst thing you can do is close yourself in a room without any human contact and do nothing. It may help for a bit being alone and think what went wrong. But if you spent too much time like that... You'll end up a lot worse.
Room 215 "Wish"
