Basic sleep hygiene, no large meals in the evening, try to avoid blue light (blue light filters for screens or avoid screens), try to cool bedoom down before going to bed. Earplugs might help as well. Complete darkness. All those nasty power leds, tape on them. I myself have smart lights so I can't make them red and real dim so as to avoid any disturbance through light.
Aside from that, melatonin ~30-60 min before hopping into bed and often an ambien 30-5 min before.
Then again that's even when I do smoke. And I'm understating my medication slightly.
For me the best substitute when I quit weed was genuinely Terry Pratchett novels. They're sort of whimsical and provoking humorous thoughts. Much like weed often does. And the books are exceedingly good natured, even the baddies aren't really that evil. Usually they're more like arbitrary concepts.
So tldr sleep hygiene and reading under a somewhat low light while the room cools down and when it gets too cold and you're getting tired of reading, close the window and hop into a crispy bed.
Should help at least. Some of these things at least. Probably. Maybe.