I like to read. Reading is a great way to take your mind off of whatever stress you're going through. It's like a little vacation for your brain (and I'm sure it's a lot cheaper than taking an actual vacation). Anyway, what you read is totally up to you but you could try that and see if that helps.
Wow...I like reading to relieve my stress too but sometimes it doesn't help when I can't concentrate.
During those times I switch and just watch anime.