The necessity for construction lines is also why i don't do much realistic portraiting. :v
Also here's my take on the C&C-y thing:
- Her hair and head outline is drawn as if seen a bit from above, and while that is entirely legit, her face doesn't quite match up to it.
- Her eyes are misplaced, as has been mentioned, but her right one more so than her left. The distance between the two eyes is generally around the same as the width of one eye, so half an eye width from the center line to the corner of the eye is what you're looking for. Also, the straight line going through all four eye corners is vertically dead center on the skull. Going by the assumption that she's viewed slightly from above, her eyes need to be a bit lower than they are. Additionally, the pupils and irises are
normally covered very similarly by the eyelids (unless one is deliberately making weird faces or if one has an eye condition); she has one eye with white above the iris and one with white below it, partly caused by a dissimilarity in the shape of the eyes.
- Without knowing of your references actual looks, the nose seems too small and is, as GUNIN mentioned, too far up. Obviously there are people without the great big honkers that i like to draw, but girls still do have noses. :v
- Mouth is placed right, but the lips are too heavily outlined and are a bit too thick on her left side considering the perspective here. The latter is a minor nitpick, though.
All that said, you've done quite well with the hair and clothes, and those are NOT the easiest things to get right. You have good observational copying skills (and that's a good thing), just gotta get the alignments right.
Also i know this has been done before, but here's my take on the violent facial rearrangement.