I really like the fact that you have tried and how you have brought the element of fire so well out.
I really can't see that well what your vision was other that Fire, but it doesn't matter.
You could think more into with direction the flames and the hair are going. Because to me they don't look like they belong together. Also the flames on the feet's are not as good as those on the background just like those on the hands, that's something you should consider, cos right now the picture doesn't look like the elements belong together, and that's a shame because, it's really pretty
Also the shades are somehow weird, maybe if you think what places will be lighten by the flames, and maybe make some arrows to another layer with show you the direction of shading.
Also you could think of the fact that flames don't look that good when they come from one and only place, it kinda eats their life away if you know what I mean.
You really do have the technique, but you need to have your thoughts on the whole picture, not only what looks good alone.
This picture really does have some kind of a impact, but it could be better, if the couple things would go together better.
I really like this picture, and I can see the time you've brought on this.