I'd have to agree with those that suggest listening to muic that relaxes you, but also lay back, get comfy, and slowly start breathing in through the nose and out through the mouth, gently inhale then exhale, focus entirly on your breathing and don't allow any errent thoughts in to your mind.
Basicaly that, relaxing music, slow breathing and focus on somthing that relaxes you, most important of all don't think about morning just relax.
Related: I know what it's like to have insomnia, it sucks, for me I could never sleep cause stuff kept creeping in to my head, I'd use white noise to distract my brain, so you could turn your tv on a low volume roll over and let white noise block out all thoughts.
Back when I still used AVG I'd run a scan with instructions tto turn off automaticly, the gentle hum of my PC never failed to put me to sleep.