I'm in a weird predicament where my body doesn't produce nearly enough melatonin, I'd had trouble falling asleep for years until my doctor tried melatonin tablets (which work like a charm). So while searching for an answer I tried loads of methods that supposedly help you fall asleep. These are the ones I remember:
•Eating lettuce(?) this was a weird one, recommended to me by a doctor
•f.lux
•Classical music
•asmr
•http://asoftmurmur.com/ --this one was really nice. Rain + Thunder + Coffee Shop together was my favourite
•Milk
•Bananas
•Good sleep hygiene
•Not playing any videogames at least 2.5 hours before bed
•Lying in bed, eyes closed, not moving and trying not to fall asleep
•Reading
•Camomile tea
•Counting my breaths