One of the most effective methods I’ve found of inducing relaxation is by listening to gorgeous meditation music. The track below is one I find particularly peaceful and I find I’m deeply relaxed after 5-10 mins.
This type of music is also great for insomnia- something which I am very familiar with- and I would say 99% effective in getting me back to sleep.
There are also some very effective relaxation meditations available on You Tube, for example:
Music and Meditation are a great way to calm the racing thoughts of anxiety or hypomania! The deeply relaxed state you are guided towards is perfect for releasing tension & stress too.