here are good tips:

-listen to relaxing music, pink floyd or bob marley for example
-smoke few hits
-drink some herbal tea (i drink some called dormiphen)
-when u drink few beers its a lot easier to fall asleep too
- concentrate on your respiration

well im doin all of those tips and i fall asleep usually in less than 30mn. it sucks i find it hard too to sleep. but i love it when im drunk i fall asleep soooo much