I agree with reading - that always helps me calm a busy mind. Other stuff that helps me is a white noise machine or using rain, wind, waves, pink noise - find one you like and stick with it. For me it was a little bit of a process to get the right noise, right volume, and find one that was long enough. This is one that I use on my phone when I'm away from home. It's 10 hours of rain noise and is pleasant and non-repetitive.
If you're OK with spending money on a white noise machine, we use the Hatch Restore which has a wide variety of sleep sounds, guided mindfulness/meditations, sleep stories, as well as a dimmable nightlight that can be any color you want and the ability to set a night time and wake up routine (like dim your light and start a sound until it's time to wake or slowly brighten your light and play a different sound/alarm when it's time to wake up). Some of the mindfulness and stories require a subscription but I haven't paid for any of it and still find it useful.
Another option is an audiobook. They're free from you local library and I really enjoy them. I'm currently listening to Tom Clancy's Jack Ryan series. Each one is probably 12-20 hours and now it's my preferred way to "read" fiction. It's also great, IMO, for long drives.
Other things that help are deep breathing for 5-10 minutes (yes, that long). If you have an Apple Watch, use the Breathe app. Or, use the following cycle: 4 seconds inhale, 4 seconds hold, 8 seconds exhale. If you're really stressed out or your thoughts keep racing this is a good technique to get off that train since you will be focused on your breathing and counting. 5-10 minutes will seem like FOREVER but it always helps me.
General sleeping guidelines are an extremely dark room (use blackout curtains/blinds - blinds.com have some cheaper blackout cellular shades), use white or other noise (fairly loud), keep the room 68*F or lower (which can be unreasonable given the season), use a ceiling fan to circulate air (if you have one), and make sure your mattress, sheets, and pillow are comfortable. I switched to a shredded foam pillow (Coop Home Goods on Amazon) where you can adjust the fill yourself, bamboo (rayon) sheets, and bought a new pillowtop mattress to replace my 10-year old one we were using.
I know it's a lot but pick and choose what sounds good for you. Another sleep aid is melatonin but don't start taking a supplement because someone on the internet mentioned it and talk to your doctor first. You could also be struggling with a mental health problem such as depression or anxiety which can be addressed again by your physician. Anxiety made my sleep a real struggle so I hope you are able to find something that works for you!