1) Calming teas and a tablespoon of pure, raw honey. My personal choice is local honey and Chamomile tea. This helps me the most with winding down and letting me get my thoughts in order.
2) Set a routine that tires you out an hour before you want to sleep. For me that could be reading, watching a show I'm familiar with, drawing, ect. Find those things that always help soothe you and pull yourself together.
3) If your thoughts are a mess, pause, and take time to organize and lay them out before bed. One of my worse fears is forgetting something like an alarm or a chore, so be sure to go through a mental, verbal, or even physical checklist to help.
Lastly, remind yourself to breathe. No, I'm serious. Breathing a steady, slow, and deep pace can trick your mind into being more tired than you actually are, and when you're laying in bed and ready to sleep, even your breathing and let your mind go blank.
But this is what's helped me, it may not work the same for you and that's okay.