When you can't fall asleep, there are ways to coax slumber:
* Carnation Hot Cocoa Mix, 10-pack, $1.74.
* Compoz Nighttime Sleep Aid, 24 tablets, $5.39.
* "Conquering Bad Dreams and Nightmares," by Drs. E. Joseph Neidhardt and Barry J. Krakow; $8.95 plus shipping and handling from Berkley Books, (212) 951-8800.