The American style is a more relaxed style. That's what you call 'casual' in fashion terms. This style is also often very sporty, which can be seen in the oversized sweaters and jogging pants. Furthermore, a good pair of jeans are very important and a nice (crop)top. It doesn't have to be very special, because usually the outfit is finished off with eye-catching accessories, like a nice belt, bag or eye-catching jewelry.