Things to avoid to prepare you for sleep are large meals at bedtime, chocolate, and alcohol. Things to help include lite bites of food (unless you have reflux), kiwis in the evening (increases serotonin), and tart cheery juice (increases melatonin). During the day, go outside for natural sunlight and some exercise and at night, sleep in a dark room with no electronics.
See the AARP newsletter, Strive for Healthy Living, Fall, 2013.
Celebration of Health Association website