I've practiced the fastest method to fall asleep for 3 months now: meditation!

When preparing to sleep, lie flat and then meditate (observe your breathing). Follow your attention as air enters through your nostrils-abdomen-hold your breath-then exhale through your nostrils, repeat the cycle a few times, and you can fall asleep very quickly.

Many times when you can't fall asleep, it's not because you're not tired, but because you're too excited/stimulated. The main benefit of breath-watching meditation is that it quickly calms you down, slows your heart rate, making it easier to enter sleep.