Check out the photo below, it's awesome!
This is the easiest way to wave hair, the healthiest, and the one that I most often use. Depending on how many waves I want, I may put as many as 2 to 6 braids in my hair.
Take freshly washed and slightly damp hair and divide it into even sections. Braid loosely for soft waves, and braid tight for tight waves. When you reach near the bottom, roll the remaining two inches of hair on a strip of cloth or a plastic straw. Tie and secure.
NOTE: Braiding the hair every night with at least one braid keeps you from pulling and stretching it in the night. This reduces breakage and helps hair stay healthy. (Happy Pinning:)