You need to isolate your model from the background more. Moving her away from the background is the easiest way to do this. You will minimize the shadow like you have here. It will also be easier to through the bg out of focus.
TC
I feel this beautiful face could have been captured better with diffused lighting. Lighting seem to be little harsh and focus is soft. Its still a nice photo and honest attempt. 7.
The shadow kills this portrait. Subject should be placed further from the background, and any shadows can be covered up with a reflecting board positioned so it is directed at the shadow. Model was very attractive, though, and you did a wonderful job on creating a nice skin tone.
This is good. She looks a little too shiny on the forehead and nose, but a little powder kills that. The bit that spoils it slightly is the shadow on the background. The way to fix that is to move her about a foot more out from the background and that will not be noticeable
Nice model. Beautiful eyes. Not crazy about the textured yellow wall. Her skin has a touch too much yellow, maybe it's the reflection off of the backdrop. The lighting and focus are well done.
Three things I think could improve this shot a lot:
1) Move the model away from the background. This will help blur the background even more (it's not bad now), it would also darken the background a bit since more light would be on the subject than the background (light decreases with a square of the distance), and the shadow behind her head would be softened and blurred.
2) Next, if you use a Flash Bracket, it will keep your flash "above the camera" even when the camera is turned on its side for a portrait shot. The advantage here would be to keep the shadow down instead of off to the side (you might not even see it in this particular shot).
3) Finally, a quick curves adjustment for contrast, even without making any other changes, would have helped this image to score higher.