I used to have terrible insomnia -- I'd often have trouble sleeping everynight, and it would take me 3-4 hours to fall asleep even when very tired. I have been able to nearly solve the insomnia fully. There are a few things I've done:
a) Exercise! I can't tell you how important this is, if I go more than 2 days w/out exercising, I'll have sleeping problems again.
b) No caffeine. No coffee, no tea, no soda, limit your chocolate as well. At first, you may find yourself withdrawing from it, or sleepy, but your body compensates for it.
c) Don't take naps. They goof up your circadian rythms.
Beyond that, get yourself on a regular sleeping pattern, and maybe consider meditation to reduce stress (although exercise is effectively proven to be the best stress reliever).
Good luck to you.
-Ankur