Somehow I came across a great method of falling asleep. I have modified it a bit and I cracked it! I made a video about that and it is working for thousands of people.
The problem is that the mind drifts away and starts thinking about millions of things, looks for problems to solve and becomes fully engaged in finding a solution to those problems. The trick is to give your mind a task that's fairly easy to do, but challenging enough to keep it engaged. Then you add a bit of self hypnosis and you have a solution that works most of the time. If you are restless, you might want to do some Tai Chi standing meditation, drink some alcohol, do some exercises or anything that will bring your body into equilibrium.
Watch the video and see what methods of engaging the mind I suggest: