belail,
Great going so far!!
I like the choppiness of the background, and really like that area right around her left armpit where you have a nice hard shadow contrasted with the softer shoulder area ~ I’m a sucker for edge contrast, what can I say! 
The main thing I notice right away is that the axes of the face need to be parallel ~ ie, the axes of the eyes, nose, lips, chin, and brow all need to be at basically the same angle ~ right now (and I know this must be hard because you are working at such a small scale) I think that they are at mismatching angles, and that is what is causing her to look a bit unnatural. Also make sure that you determine the proper central axis of the face, as this will really determine the axes of all of the important features of the face.
Overall, this is coming along really well!
I would suggest for the background, keeping it loose and desaturated, and focusing your energy and detailing on specific bits of the figure ~ ie head and torso. These should receive the most attention, as that is what the viewer’s primary focal point will generally be.
Regarding the digital bit not straying from the traditional bit ~ don’t shoot yourself in the foot. I kind of had this reluctance too initially because I felt as though I were “cheating” ~ however, now that I’ve worked with painting in Photoshop, I now consider painting with oils and brushes “cheating”, lol! With oil paints and brushes I can get a tremendous variety of strokes and tonal values and colors in a matter of a few wide expressive strokes ~ in order to do this in Photoshop, at least on my machine, it would take ages to do this, and there is no tactile sense of brush to canvas! Also, having not chemically engineered the properties of oil paints and brushes myself any more than I programmed Photoshop or Painter or Maya, I now realize how dependent I am upon certain properties of traditional media which make my conversion to the digital medium a sometimes reluctant one. So, in short, I understand your concern, but realize that using traditional media is ‘cheating’ to some degree also in that what you are using is a tool ~ just as using Photoshop or Painter is using a tool, also. 
Enough babbling on my part. Why am I awake, really? Who knows.
Keep going, and post your results! 
~Rebeccak