Generally anatomically this is a good piece! Also the clothing folds give a good sense of movement. However I think you could have been more inventive with the background and the pose of the character. Often in these sort of pieces backgrounds are often an afterthought. To really accomplish a fantastic piece you need to keep your Background in mind whilst you are planning the piece. Thats not to say the background in this image is bad- I just think you may have been able to do something more inventive. Unforuntatel you have chosen to draw in a very stereotypical anime style- you need to start developing your own style so that your work can stand out (thats not to say you should stop drawing this style) forinstance Clamp have a very individual style- ou can look at their work and instantly recognise it is theirs. This is something which develops with time but doing observational drawing can also help along the way.