Joseph, welcome to Etsy!
I think it's a good idea to use most or all 5 photo slots if possible, as the fun of shopping is looking at items at all angles since they can't be handled. Like the others have suggested, a lighter background would be worth trying too, as lighter or white will help bring out the lovely colours of your pendants. Also try taking a photo showing more of the cord too, and a couple taken at lower angles.
I noticed you mention you'll accept returns. Just my opinion, but I feel that info might be better only in policies - I wouldn't even want returning of items in the mind of my customers!
Others hopefully will chime in with some great tag ideas, but here are some suggestions I came up with: enameled necklace, enameled pendant, tree pendant, copper jewelry, torch fired
Do a search on similar items, go to the bottom of other's listings and click on 'item details' and you'll find some inspiration to help you with tags.
I wish you all the best with your new store!