[header] How to look preppy and mature [title] Start with your hair. [step] If you have long hair, make your hair messy, but not frizzy. Use curling shampoo while taking a bath, and afterwards when it's dry, curl strands of your hair around your fingers to help it get in the mood. 
It's important for this preppy look that your hair is in the right mood. If you have straight hair, keep it straight.