I think there are many things that make a person fall asleep easier or take longer. What you drink. If you drink pop with caffeine or coffee or even Sudafed or Albuterol breathing treatments they can all wire you up to a completely awful amount.
Thinking about how you feel when you go crawl in the bed can help you to figure out what needs to be done.
In stress management classes we were taught that bed is for sleeping and nothing else. Not reading or computer work or texting on the phone. Bed is the one place that is specific to sleep and needs to be set apart for that.
Read in a comfortable chair. Heat up some rice bags that you can make for yourself, put one or two in your bed under the covers then put a couple around you so you can get toasty warm then go crawl in bed.
When I was having insomnia I would heat some rice bags and play my stereo on the very lowest setting. My ears would work super hard to hear the music thereby distracting my brain so my body would fall asleep. Also doing relaxation techniques can relax you bone deep. You can good that.
How to make as many rice bags as you want. Go to Walmart and buy the biggest longest widest white tube socks you can find. Then go buy the biggest bag of white long cooking rice you can find.
Go home. Open the corner of the bag of rice. Pour rice into the sock. Fill it about half way. Too much makes it hard. When it's about half way full tie a big knot in the open end to close it.
For the really really big dense ones I heat 2 minutes but that is a super HOT rice bag. For smaller ones I do 1 minute.
When I lay down I put a 2 minute one in my bed around the bottoms of my feet so I can simply pull them away if they're too hot. I put another 1 minute bag on any sore spots, especially my back right above my shoulder blade.