Make the room completely dark, turn off the tv, turn the phone on silent and don’t fuck around with it, put some kind of white noise on like a fan at low settings, get into bed, close your eyes and clear your mind of everything except slowly counting backwards from 100.
If you partake, smoke a little bit of weed if the insomnia is really bad. Just don’t make a habit of it or you’ll end up dependent on it as a sleep aid.
When all else fails, jack off. Instant sleep aid