Here's what I noticed.
When it comes to jewelry people are attracted to extreme close ups.
For example, this girl I found, I fell in love with her stuff
http://www.etsy.com/listing/62446458/lucky-in-turquoise-gold-cluster-earringsWhen you look around her shop you will see that she takes:
1. extreme close ups.
2. Items are on white or something like rocks, slate, pottery. Very natural
3. She uses natural light (and then she lightens up with a photo editor), but also keeping the softness in.
4. Most of the time she also shows the piece on someone, so you can see where it falls and how big it is.
I haven't bought much on etsy, but I definitely ordered from her shop!
Good luck!