I would recommend just finding a way to get proper sleep, like Alex just said.
But if that's no good for you, then I'd advise to just exercise a little bit more and drink plenty of water while trying to adjust. If you're really interested in boosting more REM in a shorter period, you can check out the Polyphasic Sleep topic, located here:
http://www.learningstrategies.com/forum/ubb/Forum4/HTML/000476.html
However, whatever you do - stay off caffiene.
-youngprer
