I didn't use to have any sleeping issues, but as I age I started getting them. Sometimes in the middle of the night or around 4 AM I would wake up and am unable to go to sleep. My brain keeps coming up with things to think about and I am unable to shut it off. So I would need to get it occupied with something or do something to clear it, then I am able to go back to sleep.
Write more!
It is the best thing for occupying the mind with something useful. It really is one of the core life hacks.