Hi! I think it's great that you've been averaging 10 sales a month -- it took me a long time to make my first sale so you're definitely off to a great start. :)
I know jewelry is a competitive market, and I have so much to learn about photography myself so I'm probably not the best to give advice... but I agree it might be good to work on your photos. A light box is a good idea, there are tutorials online about how to make them that are great. I'd definitely work on using all 5 picture slots - maybe a closeup so we can see the detail and/or a picture of what the pendants look like on. I was mostly looking at the bottle cap pendants.
I'd also recommend working on your tags so it's easier for people to find your items. There are lots of good resources about SEO in the forums, but on the listings I looked at some of the tags seemed like they could use work. I'm still learning about this too - it's a lot of work but it has improved my views and sales.
Good luck!