Exercise helps tire and relax your body. Avoid other stimulants like cigarettes as well. Avoid alcohol before bedtime.
Alcohol disrupts the brain's normal patterns during sleep.
Try to stay in a pattern with a regular bedtime and wakeup time, even on weekends. Random is the key word here. About every 90 minutes the brain stem sends electrical impulses throughout the brain, in no particular order or fashion. It is like looking at a Rorschach test, a random splash of ink on paper. This doesn't mean that dreams are meaningless or should be ignored.