1. Learn your sleep position. Your "sleep position" is the position you always move into right before falling asleep. Once you know your sleep position you can move into it immediately once you get into bed.
2. Create a sleep ritual. Figure out what helps you relax and make a habit of doing those things every time before you plan to sleep.
3. Build a sleep cocoon. Experiment a bit with earplugs or noise-cancelling headphones to counteract the loud neighbors, air conditioning or a fan, and a blackout curtain to keep the street lights from keeping you awake at night.
4. Experiment with naps. You could take an extreme and try polyphasic sleep. I'd recommend something more along the lines of a quick cat nap in the afternoon when you're feeling tired.
5. Skip the late-afternoon caffeine. If caffeine can affect you for up to 8 hours after consumption.
6. Maintain a sleep schedule. "Get up at the same time every morning and go to sleep at the same time every night" says the Mayo Clinic.
7. Go to directly to bed when you're tired. If you're within an hour of your normal bed time and you're feeling tired, go to bed and try to sleep.
8. Have clean bedding you love. Take a look at your pillow, too. If it's old and the filling is clumping up, it might be time to treat yourself to a new one.
9. Exercise early, don't eat late.