One of the best pieces I've seen on these forums in a while lD
I'm envious of the skin shades you've chosen, you have a really good sense of colour. The blues you've chosen really compliment the pinks in her skin.
I quite like the lighting you've got at the moment, but her face seems a little flat for the style you've got going here. I think it should be fine if you just add a few minor adjustments. The bottom of the nose and just under it could be improved with some minor tweaking, as could the shadows surrounding the eyes. It's a bit hard for me to go into detail, so I hope you get what I'm referring to.
The dress is gorgeous, I think you've got it almost perfect. If you really want to make it stand out, you could consider adding some decoration to the edges. You could also make it flow out a bit more at the point where it is resting on the ground.
However, the sparkles in the background seem to ruin the picture in a way. I'm not against them, it's just that they're all facing the same way and are the same shape. Changing the size didn't really work. If you tell my what program you're using, I can give some suggestions to what brushes you could use.
Also, as a suggestion, if the background is water as it appears to be, it might be nice to add some ripple effects to give a bit more depth to the water. I'm referring to a technique like the one in
this artwork.
Hope that helped a bit. Can't wait to see this image finished.
Btw, I'm curious to know which program you use and the brushes you use on it, please share?