i find staying completly still works 8/10 times.

Get yourself into a position that you have worken up in before, (your body will move in the night to get more comfortable).

And basically just lay completly still, let your mind wander, but just stay comfortable and STILL (most people move there toes, legs or just shift positions every ten minutes, try to avoid this!)

Thats what does it for me.. easy, but effective.