It's a very nice picture. ^^
I think an idea to improve this picture, is to add more of a background. The current one is fine, but it's simple.
Since the wolf is already very simple, you could put a little more detail into the background.
Also, for the wolf, instead of literally drawing the picture, use the tool where it makes the lines curvy/straight.
It'll give the wolf a more clean, elegant effect to it.
I hope this helps!! But all in all, it is a great picture. ^^