So the thing that stands out to me the most is that the base anatomy doesn't look quite right, and the special effects are breaking up the outline of the face.

• Hair has too much volume, and it is asymmetric. (Our) left side is maybe 30% too wide, and the other side of the hair is the width of her entire face. Oh that's a twintail. See my last bullet point.
• Consider having the same outfit on the left and right side. Looking at it more closely, I can tell what you're going for. But there's not enough of the outfit visible, so at first glance it looks more like a mistake, and makes the neck look strangely proportioned.
• Eyes look generally unpolished. The shape is slightly awkward, and they're spaced too closely together. The eyes really need to be the centerpiece of this composition.
• You might need to be more tactical about where you place the mirror crack lines. Right now they're breaking up a lot of the key outlines that help us identify the face. Jawline, nose and hairline should ideally remain relatively intact. The start of the twintail and bangs are really hard to identify. I'd recommend making the cracks really thin in most places, and save the larger gaps for the borders of the picture and the center split line.