Body scans are a solid foundation to relaxing to get to sleep faster. I also use diaphragmatic breathing (deep breathing) with my therapy clients struggling with racing thoughts and insomnia.

The main reason diaphragmatic breathing, body scans, and other mindfulness techniques work is because you're shifting your attention away from worry and onto something else.

You can shift your attention to your breathing, observe as you release the tension from different muscle groups, or imagine you're walking through the woods after an afternoon rain--imagining the smell of the rain, the sounds of leaves crunching, etc.

Just practice shifting your attention and you'll get to sleep faster. Also works well with anxiety during the day.