Workout or be more active during the day. Otherwise, Nyquil will knock you out. Bought the new Nyquil Severe (maximum strength) a week ago to combat my cold and maaaaan...I felt like I was hit by a train as the drowsiness set in less than 5 minutes. And my cold disappeared after a day or two. Good thing I took it at night.
Lorazepam, qd. Good night's sleep. Seriously, You could try to relax, sometimes stress and hyperactivity keeps you awake. Try to massage aromatherapy oils on your wrist and neck area prior to sleeping, drink chamomile tea infusion and listen to some relaxing music like Enya or Era, or whatever so long as it's not Hammerfall.
I'd suggest you start exercising on a regular basis. It's a bit of a bummer there's no easy easy way to do it, not for everyone. However exercise in the morning followed by appropriate nourishment throughout the day at decent times will play a large factor in dealing with sleeping issues.
I work out several hours before bed, and keep myself busy during the day. I also try to read before falling asleep. But I still wake up every 3 hours, usually from a good REM sleep I've trained myself to do that though. Since I'm a type I diabetic... my blood sugar tends to rocket 4 or 5 hours in, and I need to be awake to take some insulin :P it's common, since the liver dumps protein into the blood stream while you're asleep.
I very rarely sleep through the entire night, I hate the feeling when I wake up. I feel... reanimated, like a zombie. And I'm usually more tired. I prefer waking up every 3 hours..