The character model is very attractive as is the clothing selected, however the lighting setup and the background is letting you down a little. Based upon looking at the image alone and the reflections off the dress, you can tell the lighting is a pair of emissive spheres:
- White sphere behind and left of the camera
- Pink sphere behind and right of the camera
With the lighting setup, the contours of the face are not easily distinguishable. As some advice, look into the 3 point light setup, combined with a darker background. Essentially leave the white light where it is, move the pink light behind and right the character and create a lower intensity white light where the pink light was (perhaps positioned a little lower). Then substitute the background with a darker background or simply adjusts it's base colour. The advantage of this is that the character jumps out in the image and the back light (pink) serves to differentiate it from the dark background.
In terms of backgrounds there are many options. Essentially anything with some colour variation that is out of focus as a result of using depth of field on the camera will make the scene a little more interesting.