We spend several hours a day sleeping. The exact amount that is best for us, has long been up for debate. However, if you can't fall asleep, then that can result in real problems--physically and emotionally.
Here's something I read about recently that maybe you will find useful if you sometimes have trouble falling asleep--the 4-7-8 breathing trick.
Other bits of sleep advice may be found in Eat Move Sleep: How Small Choices Lead to Big Changes by Tom Rath [AB/CD 613 RAT], or Good Nights: How to Stop Sleep Deprivation, Overcome Insomnia, and Get the Sleep You Need by Gary K. Zammit [616.8498 ZAM]
There are quite a number of picture books about sleep, and, counting sheep. One that may hold some interest for adults is Henry's Night by D. B. Johnson (a New Hampshire author/illustrator) [JP JOH]. It is part of a series of Henry books based upon the writings of Henry David Thoreau, but, in the picture books, Henry is a bear!