I hope this doesnt cross a line into intrusive or anything, but I saw some stuff with David's latest post that I thought I could help with. I did this draw over to illustrate (in more than just words) some ways to make this good drawing even better.
David, this is a really good drawing. You're progressing quickly! The thing you need to look at here are the proportions. Her arms are too short, the head is too big, and the bottom of the pelvis is way too low.
Remember, the body is about 7 1/2 heads tall (8 for superheroes), and the upper body is 4 heads from the top of the head to the bottom of the pelvis. Your drawing is closer to 3 heads tall. The elbow is about the bottom of the rib cage, the wrist will be at about the bottom of the pelvis, and the hand dangling below that.
Now, with the face, make sure everything lines up properly. I dont know why everyone says to use "rings" to construct the eye, nose, and mouth lines. It's way easier to get these features parallel using straight lines. I mean, it's more box than egg. Feel it! The face is a relatively flat plane. Same goes for the sides of the head. Once you use the box and parallel lines to get a solid face/head going, you can always give it the curvature it needs to feel organic.
I hope this helps out!