It's a good start. Very nice proportions on her face! Also I can see you are paying very close attention to getting the values right, which is good because I have some suggestions for you that I hope will help as you continue with this piece.

So here we go: values. I think you will achieve a much higher level of detail if you incorporate a larger value range. So far, you have a range of about 2-3 values in her face. Of course you may already have been intending to add more values, but I'll just take the picture for what it is just in case! Anyway, what I mean by a larger value range is you should start working with values within values. For example, some parts of one shaded area are darker than others. Also, add some highlights!

But where do the darker values and the highlights go? Well, let's see.. some of your darkest points would be the areas closest to where her hair comes over her face, the area just below her bottom lip, her nostrils and the bottom of the tip of her nose. Some of your brightest highlights would probably be the bridge of her nose, and the very tip of her nose would be brighter still. Also the upper part of her cheek. Here's a tutorial I found real quick that gives a little overview of what I am talkin' about: [link]

Now, since this is a work in progress I can't really assume how realistic you are hoping to make this, but I will tell you what I would do to make it more realistic.. First of all, do not outline the eyes. Just use value to indicate her eye shape (boy i sure talk about values a lot.. haha). This is another tutorial.. it's also for pencil art, but the concept is the same: [link] Notice in the completed picture how they showed the shape of the eye by shading in the whites. It is also worth noting that unless the eyes are opened very wide, you will not see the pupils as a full circle. Remember that while the entire eyeball is a sphere, it gets overlapped by our lids, including the pupil. It doesn't hurt to start with a perfect circle, of course.. that's actually how I start when I paint eyes. But then I would add the upper eyelid over that to give that realistic touch.

Also be careful about using bold, dark lines on the lips! I am bad at explaining stuff I think, so here is an awesome digital painting tutorial devoted to painting lips: [link]

Her hair looks good, I like the shape, but with all the blending you have done it looks a bit clumpy at the moment. It's a pain in the ass, but some strong, prominent brush strokes could help create a more hairy texture. Use slightly different shades, overlap strokes, etc. It looks like you know what your doing with the shading there, so keep it up!

It looks like you are on your way to making a very nice painting. Keep up the good work!