Fame
Famous people love jewelry. It's a fact. So the "Fame" formula is pretty simple: get famous people to like your jewelry. When someone on the red carpet is asked "Who are you wearing?" you want the answer to be your name.
Or you could be like David Yurman or Harry Winston, one of those names that's just associated with jewelry. Those people are on another level—the level where plenty of people would claw their own eyes out to wear your jewelry to a fancy dinner.
Like any other field, there's no one way to go about becoming famous in jewelry design. Hard work and talent are your best bet, but business is fickle and there's no guarantee that you'll ever be represented by the celebs walking the red carpet (source).