I saw another from a military training expert, where you think about putting all your body parts to sleep by focusing on the part and loosening it up and trying to...zen it?...to rest.
Like you think of your right leg and you feel it tighten it loosen it relax it then move to your left leg and do the same, shoulders, arms, neck,toes fingers eye's everything and while your doing that you drift off. He said they train their soldiers that to get fast sleep when they can.......something like that anyways...I don't do Ted talks....lol