anxiety

If you work out, don't do it within 3-4 hours of going to bed; it revs up your system and makes it harder to wind down. Also, you can try a nice warm (not hot) shower or bath about 90 minutes before bed---it triggers a drop in body temperature that will signal the brain that it's time for sleep. Shut down the computer and turn off the TV at least one hour, and preferably two, before retiring for the night. Use your bed only for sleep and sex, and keep your bedroom cool, dark and quiet (or if you're like me and don't like it TOO quiet, you can use a fan or a "white noise" machine to block out unwanted sounds).

And if you can manage it, try to go to bed and get up at the same times every day---even on your days off. This resets your body clock. I had to resort to this myself because I was sleeping so poorly and so irregularly that it was literally causing me health problems; once I got used to it, things stabilized and now I'm not only healthier but happier. :)