Way back when I was young, I had a friend taught me the use of what he called self hypnosis to go to sleep. First you would make sure you were comfortable. Then you would clear your mind of everything, This was the hardest thing to do. It takes practice. One technique that worked for me was to think of your mind as the sky and thoughts as clouds. As soon as a cloud, or thought, would appear, and then a little imaginary man, or the wind , or could even be a tractor

, would push it away to make the sky clear again.
When the sky stayed clear, you tell each part of your body to go to sleep. You could also tell yourself what time you wanted to wake up. Then you would drift off to sleep and wake up at that precise time.
It took some practice but it was simply amazing how well it worked. I still do the making the clouds go away part sometimes, but the others are not needed anymore. Actually with retrospect, the realization that you can control what your mind chooses to think about was the most important aspect of this technique. It can be used elsewhere at any time. It is amazing how many people don't realize that choice is available. I sometimes suspect of what causes that ability to manage your thoughts is what some people call your spirit. It could be one of the things that differentiates us from an animal.