I'm not a jeweler but I did sleep at a Holiday Inn last night. Actually my brother in law is in the business so I know a little. If you are looking for something, shop around. If you go to a Mom and Pop store, they will probably be able to negotiate more than a chain store. A chain has a margin of profit they want to maintain. They will deal but not as much. A Mom and Pop will usually deal more.
Also and I can't stress this enough, CASH in hand. I suggest you mention several times especially if you are dealing with a Mom and Pop store that you will be paying in cash. Not credit card but cash.
Some stores like to cook the books and would like to deal with cash. They will still give you a receipt which really means nothing but would like good ole greenbacks.
Also be open minded about your purchase. Alot of times the salesman can show you something he really wants to move but is not exactly what you want. Do not appear to enthusiastic and they might be more willing to close the sale.
Finally if you will be buying jewelry occasionally, find someone in the business and befriend him.
Dinner, bottle of booze, whatever. Goes a long way.