Others have mentioned some good points and the green cast so I'll let those points stand.
I think the composition could have been better. There is considerably more space behind her than in front of her. I think it would be much better the other way around. Put the space in front of her next time. Or crop the image to take some of the "behind" space out.
I also sense a little "deer in the headlights" tension in this image. Just something in the mouth and eyes. That can be overcome by establishing rapport with the model. Yes, it takes a few minutes, but doing so can improve images significantly. No magic to it... just talk and get to know each other a bit.
Just my opinion...