Here is a list of items that have been known to be effective in helping to fall asleep.
Yoga is a form of exercise that uses various body postures in order to physically purify the body. It involves stretching, meditation, and breathing exercises that are all highly effective methods for helping to prepare the mind and body for falling asleep. A Harvard study has shown that people who tried Yoga for 8-weeks ended up improving their time to fall asleep.
Peaceful, soothing music is a great way to help prepare the mind for falling asleep.
A great web site that features some relaxing music can be found at SoundSleeping.com.
As a last resort, there are prescription medications that will help induce sleep.
They are referred to as Hypnotic drugs.
They are commonly prescribed for severe cases of insomnia and should be considered a last resort due to their addictive nature.
To learn more about this class of drugs, refer to this Hypnotic Wikipedia Article.