You want to have her be the focus of the drawing, so be sure to draw the audience's eye to her by making the background appropiately. What I mean by this is the following:
If her dress is to be a light colour, make the background with dark colours, preferably cool and neutral. The opposite is applied to a dark dress, naturally. Also, it may be a wise choice to make the background seemingly blurred or nondescript.

Additional structure and direction of her dress and wings would be best, otherwise, she will appear flat and quite boring. Some texture given to her lips would be wise.

As for that of critiques, the features of her face and hand are too strikingly akin to that of a man. A smaller nose and hand, with less of a prominent chin would shift such a fault.

And I agree with gixxerman - a glow would be most appropriate, and would call on the paintings of ages past, which would be a wonderful subtlety.