I've tried all the usual sleep hygiene rules in the past, but it never really worked for me. It just made me more obsessed and anxious about getting sleep. Instead what helped me more than anything was to let go of the fixation on sleep hygiene and just generally stop caring too much whether I sleep or not. Obviously I still avoid stuff like caffeine and screens in the evening and go to bed at more or less the same time every day, but other than that I just think, sleep or no sleep, whatever. I still have insomnia a lot, but it's better than it was, and at least I don't have as much anxiety about sleep anymore.