I think most of your photos are beautiful, and don't need changing. Especially, I like the ones with the turquoise box as a backdrop.
Having said that, I just bought a pair of earrings on etsy, and the photos were beautiful and very artistic, but the actual earrings turned out to have a way longer 'drop' than I had imagined. This was in the description, but I didn't measure, and a photo on a model's ear would have helped. I am not sure what this means for you, other than if you have earrings that are really dangling, you may want to be extra careful with your description.
And yes, if you go with a mannequin, it should be life size, otherwise you open a can of worms!
Best of luck, but I think you are doing great!