Depending on how old you are, but generally Dominicans tend to dress nice and don't normally wear shorts and the like when going out clubbing. Dress nice with nice jeans and shirt and nice shoes or slacks and nice shirt and again nice clean newer shoes. Pleas DO NOT wear those hawaiian tourist shirts with shorts and sandals unless you want to stick out like a sore thumb, which you said you're trying to avoid. This is probably the biggest mistake tourists make when visiting The DR. For some reason they think that since it's hot most people go around wearing shorts when in fact Dominicans tend to dress up a lot more than people do here in The US, for instance. A lot of places won't even let you in if you are wearing shorts.
