About 20 years ago I met an elderly woman who told me that she had some kind of problem with depression. She said that the treatment she found most effective was self-hypnosis. She explained that every day she would take some time to practice this. She said she knew when she was in the right relaxed state when she could feel a sort of buzzing feeling in her lips. I have felt that feeling before when I was just drifting off to sleep, so I knew what she meant. But I do think that somewhere along the way I have learned some self-hypnosis techniques.
When I was a child, if I had trouble falling asleep, I would relax each part of my body, starting with my toes. I don't remember anyone telling me to do this, it just made sense to me. I would work to put each body part in the most relaxed and comfortable state possible before moving on to the next. I did this quite often, and I think it has really helped me to learn how to relax.
Every time I go to the doctor or dentist, and lie on the chair, I find myself totally relaxing. Some people tense up when they get in that position, but I do just the opposite. Today I went in to have an ultrasound of my my thyroid. By the time she was finished, I was so sleepy I felt like I needed a nap. I can't actually sleep in that position because they are usually poking and prodding me, but I can totally relax.
I think being able to isolate a muscle or joint and tell your brain to relax it is a powerful tool. I'm sure most people have had the experience of getting a shot, and having the nurse tell them to relax. Some people can relax, but those who can't feel the shot the most. Try this out some time. Try relaxing each body part when you are trying to fall asleep. And pay attention, and see if you can feel that buzz in your lips.