Going to bed at the same time each night helps one ward off insomnia. Your body has it's own natural sleep cycle, called the circadian rhythm, and keeping a regular sleep routine works well with your circadian rhythm to promote good sleep.
Napping during the day does not help. Avoid naps if you can but if you can't, make them short; 10-20 minutes at most.
Exercising each day also helps but don't do it too late in the evening as it could interfere with falling asleep.
If you find you can't sleep, try visualizing yourself floating on a comfortable raft on still water. Imagine yourself laying there, totally relaxed, safe, and at ease.
Relaxation techniques can help against insomnia. While laying in bed, try tensing your leg and arm muscles for a few seconds and then relax the muscles for a few seconds. Repeat this five or six times, or until you begin to feel relaxed enough to fall asleep.
Sleep in a cool, dark, and quiet room without any pets in the room.
And finally, a turkey sandwich and some milk before bedtime will sometimes do the trick to get you sleepy enough to doze off into slumberland.