The candle idea is good, just make sure to get one in a glass jar (something like a yankee candle) and put it on a safe surface away from curtains etc. in case you accidently fall asleep whilst leaving it on ; if you go for a scented one, go for a scent that relaxes you and you relate with sleep (for me I go with fresh Cotton when I’m trying to chillax in bed on a bad night; had sleep difficulties since I was a child and one of the things I always associated with a good nights sleep was slipping into freshly laundered, crisp and warm cotton beding).
Some relaxsing and softly playing music can help, however you should not go for anything to fast beat: meditation music is good - this is a good example: https://www.youtube.com/watch?v=OB4z9VpGN9A
Think hard if anything is stressing you in life: if you have any deadlines getting close that your procrastinating over get them out of the way, if something is worrying you talk about it to someone kind even if you feel thay can’t help or wont understand, if you have financial problems talk to the bank or the person who you owe so you can get it sorted out, etc.
When I can’t sleep I make up story in my head, generally something stuped and fanfic-ish but it helps me If you try this don’t try to make it good - that will just keep you upand its lost in the morning anyway lol, also don’t make it soumthing stimulating for the same reason… thats all I have