Very nice and neat! Her lineart is very clean, which is a major plus. The colors all work well together, and you set a nice mood with the background. Now for the critique: 1. The line going down the middle of her neck should be muted. It is there for emphasis, I understand, but the way it is currently drawn implies that is simply one side of her neck, and that her neck is tiny and not centered inbetween her shoulders. 2. You're good at drawing breasts! You were able to make the lines very smooth. Try to bring this skill into her nose, where the nostril looks jagged and strange. Her lips are also turned downward on one side, making her face look a little droopy. Try to even everything out by drawing sketch lines that you can erase later (a centered line down the middle of her face).
I would also like to see more detail in her face and her close, since she seems like such a strong character. Overall I think this is a good piece. Keep up the good work!