there so much to learn. read threads and even read other shops critiques, it can help you with yours.
read about seo. this will help you set up your titles in a way to be found. your title and tags should be words and/or phrases the customer will use in the search box. I noticed on a necklace with charm you didn't have any tags with the words necklace, pendant, or charm. use multi word tags too.
your pictures are probably something you will have to do over and over until you get it just right for your shop. you might have to take them outside, use an editing tool, or light box. I use fotofuze.com
you can play around with banner ideas on this free site.
http://www.bannerfans.com/banner_maker.phpgood luck!
giving this a good bump. I'm sure other out there can help you too. by the way, I only have 15 sales so......