I always listen to a novel on CD, on a Walkman, in the dark, in bed, earbuds in, with my eyes shut. At some point, I alway fall asleep, for several hours at least.
I repeat this whenever I awaken, often several times before morning.
At present, I am listening to “Possession,” by A.S. Byatt. The story is so confusing that I listen to each CD twice.
It’s not a bad system; I have stopped fretting about insomnia.