Add a motorcycle jacket

A good motorcycle jacket improves every outfit; it doesn't matter if its jeans and a T-shirt, a formal gown, or gym clothes. Black leather is the classic choice.

Do a half-assed tuck job

Whether it's a sweater, a tank or a collared silk shirt, just grab that middle front piece, tuck it down, and watch your style increase instantaneously by a factor of 10 (at least).

Always wear sunglasses

Even when you're inside. Even when it's dark out. Your eyes will adjust eventually. And besides, sunglasses are way easier to put on than eye makeup.