Ahhhh- perhaps a little leg for the next picture similar to this- she looks out of balance without it, and props always make a picture interesting. You should only crop stuff that isn't needed to enhance the picture Leaning on a wall or what is imprortant. Experiment a little with the ponytail- maybe a plait or something would be cool too
Naugh- don't erase it. If you want to improve on this pic, put it against the light and re draw it agains tthe old one Unless its still in pencil only....