I've had long hair most of my life, and as far as I know, there is no secret to it. Takes me about 7 months of growing from about 2inches to reach my shoulders(between 14-18in). I shampoo/condition my hair 3 times a week, and regular wash the rest of the days, and it always looks nice and full. For me, at least, shampooing every day makes it overly bushy and unmanageable, but like I said, its different for everyone.