I think most of it is the way her curl is but I can get crazy volume like this by diffusing my hair a lot. Do it upside down while hair is a bit damp still with or without product. And I put hair spray on the roots in different sections and diffuse too for extra volume. Good luck
Originally Posted by Pinupdollrawr
I totally agree with this and with the comment about getting the right cut. I would add that advice to try limiting the amount of product you use and/or using lightweight products. I would apply only what you need to keep your hair moisturized.

Once your hair is dry you can increase volume by gently pulling out the roots using your fingers as a comb/pick (some people use an actual pick). If you choose not to diffuse it helps (me at least) to flip the hair upside down a few times during the air drying process and scrunching the curls upwards. All of these things increase volume very well. If your hair is naturally thin/fine you may need to finish with a hairspray to hold the volume you've created.
Hair Stats (CG since 3/31/12)
Type: 3c/b; Density: M; Texture: F-M; Porosity: L-N

Cleanser: DevaCurl Decadence No Poo
Conditioner: DevaCurl Original One Condition
Leave-in: DevaCurl B'Leave-in
Stylers: DevaCurl Volumizing Frizz Free Foam, DevaCurl Beautiful Mess, DevaCurl Flexible Hold Hairspray
Refresher: DevaCurl No Comb Detangling Spray
Finisher: DevaCurl Shine Spray