Melatonin - a natural sleep hormone. Take about 6 mg before bed and use it every night for 2 weeks. Re-regulates your body for sleep. Another tip is a large mug of very warm milk - add a little sugar and vanilla extract and drink slowly... helps you relax.
Listening to white noise is a commonly accepted method for falling asleep. White noise can be sound like the static on a radio or running water, a gentle blowing fan, anything like that. You can also try recording these sounds as well and put it on a continuous loop.
Maybe put something dark over your eyes, but on a biography channel (without a lot of sound behind narration) - like someone is telling you a bedtime story - make it interesting, but not an exciting one. Also I've found some warm herbal teas work. Insomnia is no fun especially when body is dead and mind is racing. I will resort to sleeping aids if I have to.
Do you consume caffeine? Caffeine can stay in your system for 10+ hours after you consume it. For many people it lasts longer.
If caffeine might be the cause you can try Rutaesomn. It is a natural sleep aid that speeds up the body's natural process in eliminating caffeine. This allows you to continue your caffeine consumption lifestyle and still get the sleep you need when you need it. It can also be taken safely with other sleep aids such as melatonin.