Awesome necklace! I love The Hunger Games. Very great book series. Did you make the necklace, or did you buy it somewhere?
The focus on the photo is kind of off. You don't notice it too much in the small thumbnail, but looking at the full size image you can definitely see that it is out of focus and blurry. Did you use auto focus or manual? Sometimes auto focus gets confused, especially when you're taking a close up photo like this. You could try backing up a little bit so the necklace isn't so close, or using manual focus so you can see exactly how it's focusing. If you really want to do more close-up photography like this, I'd suggest investing in either a macro lens, or a macro filter. The filters are surprisingly cheap ( [link] ). Just make sure to get one that fits on your lens.
I think the background could be more interesting. Right now it's just a plain pink (I'm guessing skin?). I think if I were to take this photo, I would have tried hanging the necklace from a tree outside and using a low f-stop so the background is nice and blurred (keeping the necklace pendant the main focus), but then would have some interesting color and shapes in it.
Try experimenting with different compositions. Right now you have the necklace right in the center of the photo, but could it be more interesting if it was off to one side? Consider the rule of thirds ( [link] ) when you are looking through your viewfinder.
The lighting as it is isn't bad. It has a clear highlight and you can tell what the texture and shape of the necklace is. The only problem is the harsh shadow it casts directly onto the background. It jars the eye a little bit. I think it could be more subdued using diffused lighting. You could do this by shooting outside on a cloudy day, or putting some sort of diffuser in front of the light source. This could be as simple as some wax paper or tracing paper.
I hope I have given you some ideas for future photos. Definitely keep working hard if this is something you enjoy.