50mm 1.8 - Attitude

[nellyp]

Have been using my 50mm 1.8 for the last few days and finally think i'm getting the hang of it (zoom is so easy). I love this expression but am not totally happy with the shot (exposure or something?) - any advice on what i can do to improve it?
http://farm4.static.flickr.com/3492/3215225544_6eeec7025d.jpg