Do a test to find out if napping affects your sleep. Avoid exercising just before bedtime. It may keep you awake. Make sure your feet aren't cold and that the room temperature is comfortable. Try drinking a glass of warm milk with honey at bedtime.
Some people recommend the amino acid L-tryptophan.
Stay away from tea, coffee and chocolate. They will keep you awake. Avoid loud music, big meals, arguments and exciting television shows that might over stimulate you at night. Don't eat a heavy meal just before you plan to go to bed and avoid caffeine, alcohol and nicotine in the evening. Make the countdown to bed a relaxing routine that keeps your mind off the day's problems.