Click on the image on the right to see the entire sketch at super-high resolution.
Below are my comments on specific details.
People point out her eyes when they see this sketch, but I think the lips and nose are by far the best part of the drawing.
This detailed rolling line demarkates the light from shadow on her neck and clavicles. It's the first step to complete shading.
The side of her face here is not very good; it's too indistinct. Just a gray mass. But I like the few wispy hairs that escaped her cap.