This one worked for me last night. Having read all the stuff about not worrying about it, I decided to give it a go. I just lay there thinking "right, I'm going to be awake, but I'll let my mind drift where it wants, just shove any unpleasant work related thoughts out of my head." I'm not sure if it's just me, but when my eyes are closed I can see odd patterns of light and dark, so I decided to just relax and "watch" the light patterns. Next thing I knew was when I woke up at 5.30am. Five hours in total! Result!
Oh God I sound like a psycho....