For him: A preppy hipster combo. An untucked button-down shirt with a tie under a tank top, or a shirt and tie under a hoodie. Oversized headphones, a messenger bag, and a puppy-dog attitude add to the character.
For her: Start with the hair: a fringe is a must. Anything you wear must be blue, vaguely retro, and feminine. Summer is a big fan of dresses, but trousers and a blouse, like she wears here, work too.