from your friendly neighborhood non-faa doctor:
1. no caffeine 12 hours before sleeping (will help you sleep better)
2. beware of sleeping pills, some are NOT approved for use in pilots per the FAA (Lunesta is one i think...go check with "ask a flight surgeon")
3. the bed is for sleeping and sex....that's it. No TV, no books, no eating etc.
4. engage in good "sleep hygiene" This covers a large number of ideas, so here's a link from one of the founders of sleep medicine (Dr. Bill Dement):
http://www.stanford.edu/~dement/howto.html
5. Avoid TV and computer about 3-4 hours before trying to sleep. Both set your brain into an increased alpha-wave pattern....bad for sleeping.
6. exercise and such as other have said is a very good idea.
7. Multiple studies have shown that, despite caffeine and other stimulants, you are still a dumb-ass if you haven't slept enough. Reaction times are slowed, thinking is muddled, logic becomes more illogical etc.
...hope that helps