Audio books and AM talk radio are the answers for me. Music, especially popular music, doesn't do the trick, as you want to listen to it too much. There are also too many memories tied into music you like to listen to. Human voices, however, are so much easier to fall asleep to, and if you leave the AM radio on all night, you'll never have memories tied to anything, as the enws is often, well... new.
The other trick, I've found, are GE Reveal™ light bulbs. They actually replicate pure white light, giving you a natural light spectrum. This isn't as effective as the lamps built to simulate natural sunlight used to reset your biological clock, but it's much easier on the eyes when you need to sleep, especially as a night light or small bedside lamp (which I leave on from time to time while I listen to the radio).
I also follow a specific ritual of exercise every other day later in the evening (typically I worked out from 7pm to 10pm at college). This doesn't have so much to do with sleep, but rather, putting your mind at ease by multitasking. By watching your favorite prime-time tv (in my case, "24", "House", "Mythbusters", and "Battlestar Galactica"), weight-training, and working out some of your frustrations with physical exertion, you feel more relaxed, like you've managed to be productive regardless of how much things have piled up out of control.
Also, in my case, the exercise often led to quite a few answers to problems I ran into (academic and non-academic). I'd be on the treadmill, about to collapse, and suddenly a few solutions I could take to reach an answer to accounting would pop in my head.
Did I also mention that there is a new fad in neurological research based on IQ trends related to cardiovascular exercise? Apparently brain cells can be replaced instead of permanently lost, and regular physical fitness over an extended period of time seems to help enhance IQ, communication between the two hemispheres of the brain, as well as neurotransmitter density.
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My motto:
Study like a scholar
Act like a gentleman
Dress like a soldier