If your hair is wavy:

Spritz a volumizing hairspray all over damp hair. Using a diffuser, blow-dry the crown of your head with a round brush, lifting your hair at the roots. For the mid-section and lower part of your head, blow-dry without a diffuser; Use a curling spray and scrunch as you go. Finish with a texturizing spray and scrunch some more if you want added "messiness."

If your hair is straight:

Spray a volumizing hairspray on damp hair. Blow-dry while gently tousling and scrunching. With hot rollers or a curling iron, curl dry hair from the crown of your head down. Use a spray gel to hold the curls and gently wrap your hair in a scrunchie at the front of your head. Sleep on your 'do. In the morning, use a texturizing mousse and "mess up" your curls by tousling and scrunching.