First of all, this is a great manipulation! I can see the work and time you put into it, so for that, well done. It is a very neat concept and was executed fabulously.
The first thing I notice is the edges. On her hand, the fingers have cut-and-paste edges. If you look at the skull the raven is standing on, you can see some white-ish area. The edges of the candle, the raven and the black box thing are all a little off. As odd as this may sound, the top of her dress is also a little strange.
The lighting is very good and the dramatic shadows are very good.
The candles don't look like they belong on the skull. The one on the front has one end melting onto a awkward place on the skull. It looks like it isn't melting in the right place, if that makes any sense. With the candle in the back, you can clearly see where it meets the skull. Maybe a few pieces of dripping wax would help it flow a little bit better?
The background is a little fuzzy, which may just have been the stock, but it makes the background seem a little...detached from the picture.
An over-arching texture that goes all the way across the picture would help it flow a little better.
Overall, this is a really lovely piece. You chose some great stock and did a great job putting them together.
Thank you so much for taking the time to give me your honest input!
I just switched computers - on my old laptop I couldn't even see the areas on her fingers or the white area on the skull by the raven. I took another look at it after seeing your critique and I can see it now (on my new laptop), so thanks for pointing those things out to me!
I also totally agree about the candle - I wasn't quite sure how to make it look right without just mangling it