Limit Caffeine and Alcohol
Although alcohol can make you feel drowsy and may actually put you to sleep, it has the unpleasant side effect of waking you up later on in the night with a headache, stomachache, or full bladder. In addition, once alcohol's sedative effect wears off, there's a rebound effect that actually makes you more likely to have trouble falling back to sleep.
Caffeine, on the other hand, stimulates your brain. Limit your coffee intake to two cups a day. Starting at noon, consume no foods or beverages that contain caffeine.