I don't think it's a huge news flash to retailers that men and women approach shopping differently. A recent article in the Financial Times reports on a host of policies retailers throughout the world have implemented to get men into their stores and, more importantly, to stay there and shop.
Of course jewelers have an inherently more difficult job since the bulk of the product probably is made for women. Recent conversations with my male friends (most of whom make decent money and have significant others they would like to spoil), reveals they are absolutely terrified of jewelry stores. They find them completely overwhelming and are convinced that making a purchase at a jewelry store (especially one without price tags on its products) means they're being ripped off.
Studies show that men do plenty of research before buying a diamond engagement ring, but my unscientific survey reveals they do hardly any preparation before buying a necklace or bracelet as a birthday present for a girlfriend or mother. If you can help get these first-time shoppers through the experience, I bet they would come back for more.
The trick is to not speak down to these guys. Patiently answer their questions and explain why certain things cost certain prices. Ask about the woman for whom they're purchasing and make plenty of suggestions. These guys want and need guidance, so give it to them. If they walk away with a gift that made a girlfriend happy, they just might return for an engagement ring that would make her even happier.