SLEEP. On a schedule---regular bedtime, regular wake-up time, every single day including weekends. Do not deviate from it for any reason other than a true emergency, like rushing your mother to the hospital. If you can't sleep, get up and do some low-stimulus activity like reading a boring book, then go back to bed when you get sleepy.

Lather, rinse, repeat if you still can't doze off within 30 minutes. In the meantime your body will be getting rest even if you're not sleeping well, and after a while it becomes routine and your body becomes trained to get sleepy around the same time each night. I tell you, this helps immensely---I didn't believe it until my pdoc pretty much demanded that I try it, and I do think it's helped me to stabilize even when meds weren't doing the whole job.