I like your line work on this piece, especially on the hair. This is NOT meant to be a criticism against this piece, but rather a suggestion for your technique in general. While tightening up your lines can create a cleaner looking piece, it can also be more restrictive. Have you tried loosening up your lines and doing some sketchier pieces? Something about your line work suggests to me that you could do some interesting pieces if you tried a loosening your lines. Tight line work is over rated in my opinion.