A friend loaned me the book 'Curly Girl' (which I would never have bought because I don't have curly hair/rather a wave) and I followed the routine in that book. After years of straightening my hair, it took a couple weeks for my hair to start being wavy again but as each week passes (it's been 3 months), it's gotten healthier and wavier and back to what it was when I was a kid. I recommend it. There's a wavy chapter in the book. Very helpful.