Did you make that from scrach or did you just trace it? But at first eye's glance it looks ok but now that i look at it more careful i can see alot of mistakes such as ;
the right hand looks dodgy, like it has lumps in it.
the left hand dont really look realistic , and i think you should add some more shadow on the dress itself to make the hand a bit more realistic.
The breast area and up look unstraight, the face looks like it has square bits in it, the eyes look dodgy. There are a bit more like the dimple in the neck, needs the opacity a bit higher and placed a bit more up-right.
Dont take this as a flame but something you can improve on.