How do you cure insomnia?

Ok, I wanna know how to cure my insomnia. For the past few months I've been sitting awake until 3 in the morning because I can't fall asleep. I took sleeping pills but they didn't work. And I end up crying because I'll be sitting up trying to fall asleep at night and I get so d*** annoyed and upset. I tey to not use the computer or tv one hour before going to bed, excersise helps but come on, I really don't have the time to do that every day. Please help me, I really need help.