1. Wear something really small with something really big.
A crop top with a ball skirt. An oversized top with cut-off shorts. Looking fashionable is all about playing with proportion and contrast. Not just big with small, but also hard with soft, tight with loose, and heavy with light.
2. Add a motorcycle jacket.
A good motorcycle jacket improves every outfit; it doesn't matter if it's jeans and a T-shirt, a formal gown, or gym clothest. Black leather is the classic choice, but it's not a must. Colors, prints, embellishments, whatever! It's all good.
3. 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.
4. Wear your jacket on your shoulders.
Don't think of your jacket as a jacket. Think of it as a cape with sleeves. Sleeves you are never EVER to put your arms into.