innoxist said:
The biggest problem I see with this picture is her eyes. The edge of her glasses cyut right through her eyes, distorting the eye balls, very awakward and unfalttering. This is obviously a posed shot. You should have noticed this and have her adjust her glasses accordingly.
On the topic of glasses, the light reflection off her glasses is very annoying.
Other things - messy hair, oily face especially the forehead, these are things you can control.
Somehow, how the pen is resting on her chin does not look natural to me.
The composition has that posed look. I believe your intention is to capture her in a moment of deep thought. So, even if it's posed, it must not come across as being posed.
Anyway, keep on shooting.