A great way to shut off your brain and relax your body to prepare for sleep is to do a progressive muscle relaxation exercise. Here are the directions:
Lie on your back and bring all your attention to your body. Begin a process of gently tightening and releasing each muscle group, starting with your feet and working your way upwards to the top of your head. Hold each muscle as tightly as you can for about 5 seconds, then release it completely and see if you can notice the difference between the muscle tightened and the muscle relaxed. Move onto the next muscle until you’ve relaxed your entire body.
Anytime your mind wanders, gently bring your attention back to the tightening and releasing of each muscle group.
This technique was developed by American physician Dr. Edmund Jacobson in the early 1920’s