Use a volumizing Shampoo and mousse. You have to use product, but a little dab'll do ya! Don't go overboard. If your hair is long, the sheer weight of all that hair will keep curl from staying in. Sometimes, the texture of hair (fine or coarse) will determine if curl will stay in or not. For example, my hair is straight as a board, very thick, and very fine. If my hair is clean (i.e. just washed and dried) it is harder to style ( I do use mousse and gel, hairspray, etc. everyday). For someone with hair that is more coarse, it can be styled easier, just because of the texture.
I recommend the following products:
Halo Bodifying Volume Mousse
Halo Bodifying Volume Mousse
Tigi Superstar Thick Massive Hair
Mastermind Bite Me! Hair Candy
TIGI Hair products