I don't wanna seem too mean but there are quite a few things that are wrong with this drawing. First of all you need a light source and make your shadows fall accordingly. Secondly I would advise you not to use default blur brushes for your shading. It usually just turns out mediocre. I would advise you trying some custom brushes of some sort if you have the possibility. Also you might wanna work on your anatomy. The width of one of her hands is about half of the width of her chest. Also the fingers look stubby. They're also too big for the forearms. You might also want to work on your cloth folds and such. Otherwise I wish you luck!