It's tempting to emulate the protagonists on network cop shows and use sunglasses as a way to look serious. Instead, ditch the black rims and go with something acetate and cheerful. Lighter rims will make you look friendlier, since they don't accent the hard lines of your brow. If you're an old-fashioned type, go with something in the Clubmaster mold. More of an extrovert? Try clear frames. And if you're driving up to the party in a convertible, be sure to wear some thick, seventies-style aviators.