Lovely work! Love the raw strokes for the hair.. the smooth skin the outfit, awesome tiara or headdress! And the light dancing around her legs reminds me of something but i just can't place it.. hmm i think it was a nightlight i had as a kid LOL!
Very cheap and easy, grab a photo of some smoke against a black background, put it on your canvas, and then set layer mode to colour dodge. I don't really like these kinda tricks but I felt that its what the client wanted so heeyyy