I imagine myself having a conversation with someone and try to make the conversation very detailed. It's usually too much for my tired brain to handle and I just fall asleep
I usually just toss and turn in bed whenever I can't fall asleep, too...but, perhaps you could try exercising, going on walks, doing something active that makes you a little tired before going to bed. I remember dancing to 80s songs like crazy at night lol, and I didn't have much trouble getting to sleep afterwards.
I usually can't sleep when I think too much about my life, so I have to drown bad thoughts out by watching TV or listen to modern music that doesn't trigger any more old memories.