Something about the skirt on the dress, hmmm, I'd ditch the skirt part leave the bodice and give her legs an icy tecture that goes up into the bodice, white hair or pale blue is icier, white skin with frost on it would also add to the "ice" queen look, as for the background you need some height variation, either pillars on either side same as her height or smaller mountains to give distance, and a pale blue overcast sky would also add to it...I wish I knew poser better, I could give you an example...all this would add to your image...IMHO..=)