What makes a girl special? or do you mean what makes a WL special?

Two different answers really, if it's the second answer that you after, to get a customer to walk in the door, it has to be the LOOKS first and foremost.

Beautiful, young and be fit, if not go get some micro-shaping or plastic surgery (but don't over do it), exercise and learn how to do nice makeups. Then you have to get trained to know the art of sex. Then finally just be yourself.

That should be enough to become a popular WL.