I have two options: straight or naturally wavy. If I'm going for the wavy look, after I shampoo and condition, I towel dry, use a root lifter spray, get out the dryer and put the diffuser on it. Then I scrunge some gel or mousse all over and dry small sections with the diffuser. I also be sure to dry under neath with my head hanging down.
If i'm going straight, my hair is dry and I simply take small sections of hair and straighten with a good iron I use Instacure from great clips to combat dryness. My hair is terribly thin, so the wavy look helps give it body