1. set a sleep time and stick to it
2. no computers, TV or phones in the bed room
3. start to exercise. Start with taking a walk and work your way up from there, if you can
4. start to de-caffeinate. Take this one slowly, cut back a bit at a time
5. 1 hour before bed time, stop playing games or doom scrolling your phone. Read a book or listen to music

You will go completely insane for a while, but it will help you sleep.