Drink water.
Relax before bed and avoid stimulation.
Do not do anything other than try to fall asleep in bed. If you lay down, do so with the intent on laying there. Do not read in bed, watch TV in bed etc.
Eat turkey before hand for the L-tryptophan, and/or melatonin. (Preferably melatonin)
I highly recommend not using any sleep aids. Just proper preperation beforehand is enough for most people. You can very easily build a psychological and physiologic dependancy.
Read up on how the body works when it comes to sleeping if you're having trouble sleeping and then apply that knowledge to your situation.
Most people just choose popping pills because it's easier than avoiding smoking, eating right etc.