This is a very basic answer.

Routine and melatonin. Make a point to get active during the day, and when it's time for sleep make it the same time every night, and take some melatonin. It's not as potent as sleeping pills, but it's what your body creates to put you to sleep anyways. The idea here is to force your body to get itself back into a natural day/night cycle. The being active will help increase serotonin for wakefulness during the day. The melatonin at night basically is doing what your body would be doing itself...manually.