Do more! It's a very small piece, and there isn't much to it. It just isn't very interesting. Use your imagination. Give it a scary face, or some sort of cool design. Maybe a nice background.

If you want crits, I'd say do some selective outlining, in other words, change the black line around the blue part to a dark blue, and the black line around the tan part to a brown.

You also might want to add a little contrast to the colors. Contrast is your friend.