You can also download the sounds of gentle waves on a beach, crickets chirping and frogs croaking on I-tunes. I have a whole collection of nature sounds which are very pleasant for inducing sleep and drowning out the sound of noisy neighbors.
You also need to have a very dark room, either get black out curtains and/or a roll down shade, or simply get a dark blanket and either use nails or some type of inexpensive hooks to hang it (so you can easily take it down or push it to the side when you don’t need it to be dark any more).
I also found a very easy yoga CD which really relaxes me. This one s called Am and PM Yoga and it’s for absolute beginners, so even if you’ve never done any yoga, this is more like stretching and simple relaxation techniques.
Don’t eat a big meal, nor anything spicy before you head for your nap.
Read a chapter in a book before you head for your nap. Don’t use your computer for about an hour before you head for your nap.
And like some of the others have said, sometimes a recliner is a better choice than your bed.