I love the soft shading, and the colours are gorgeous. The anatomy seems to be alright too. The contrast in this picture, however, seems a little off and the beautiful background could be a little darker, or maybe have more shading in it. It looks kind of washed out and the girl's dress sort of disappears into it at some points.
Maybe that is the effect you were looking for, but I think you could put more darker colours into the background and possibly the dress. Some of the shading on the folds gets too dark and there could be more turquoise or teal in those shaded areas, along with some lavender, pink and periwinkle. With all the white, it's very hard to pick the foreground out from the background. I did the squinty-eye test that I learned about in some design classes, and most of the foreground just disappeared into the background, and I couldn't make out hardly any of the background details except for some of the shaded parts of the roses.
I don't know if you're using the dodge/burn tool for shading, or just using white for highlights, but I'd recommend using light non-white colours for highlights, like for the roses, yellow, green, pink, lavender, blue-green, and different hues in the blue/purple area.
Also, try not to be so dependent on special brushes and gradients for your backgrounds unless you are designing for web layouts, business cards or shirts, etc.; paint it by hand and paint your own gradients using a blended colour brush. Your art will really improve if you do so.
Anyway, this is a really nice picture and I hope you keep improving.