I've had the most luck with cardio. When I go to spin class first thing in the morning, I am basically knocked out that night. When I don't, I wake up sometimes 4-5 times throughout the night. The more consistently I do cardio (ideally every day), the better I sleep... sort of like a consistency bonus.
Some things others might have already mentioned that are supposed to help:
- Don't lie in bed for more than 20 minutes if you don't fall asleep. Ideally go to another room until you are ready to try and sleep again
- If you can't sleep after 20 minutes DO NOT use a screen. Read a book instead, or meditate.
- Don't use your bed for anything but sleep and sex
- Don't have a TV in your bedroom (or ideally any screen)
- Don't keep your phone by your bed. If you must use it for an alarm, keep it out of reach. Ideally, get an alarm clock, and keep your phone in a different room
All of the above are supposed to "train your brain" that your bed is for sleep. In this day and age a lot of brains thing beds are for watching TV.
Lastly, there is a therapeutic modality called "CBT for insomnia" which is evidence-based if you can find a therapist trained in it. As I understand it they go through all of the above and then they have you measure your sleep schedule and adjust your time in bed accordingly. I.E. if you only sleep a total of 1 hour each night and get up at 7 AM they'd have you not go to bed until 6 AM. Then gradually increase the time asleep back from 6 AM until you're on a normal schedule. I think they also have you keep a clock out of sight so you don't get anxious about what time it is.