how to make hair grow longer?

Hi! I have straight, brown long hair that goes to mid-chest length (about 6-7 in below my shoulders) and I want to grow it to my waist. I`m going to dye it dark red tonight, so please take that into consideration. How can I treat it best so it will grow that long? I use Herbal Essences Fruit Fusions Color Protecting shampoo and conditioner, and Rave 2x Smoothing Gel. I don`t blow-dry or heat-style.

Thanks!