-force yourself to get in bed really early
-set an early alarm to make going to be late hell
-turn on a movie on a device or tv and leave it dim and really quiet
-think of something that makes you happy
-think of ideas
-take a shower beforehand
-wear something you find comfortable
-spend some time just doing homework beforehand
-listen to calmer music beforehand
-smoke weed/j
-close your curtains (where I live it's bright up to even 9)
-read a book or play a simple Gameboy game (like Mario Brothers)
-write down your thoughts or a story or draw
-take melatonin (but only if you literally CANNOT go to sleep naturally)
-if you must use your phone use it at a dim brightness and at greyscale. build something in Minecraft, browse Wikipedia, turn on some video and prop it up or draw digitally.
-play dress-up before bed (dead serious this really helps sometimes)
-work harder physically during the day
-do something repetitive or simple. I reload a model gun over and over again.