That picture is really horrible. It does remind me of myself when I started drawing, back then. I'll give you a few hints.

Get used to draw bigger, Lab. Small images are hard to detail and work through. They're specially hard to mess around with because your eraser will most likely remove half of the character and they look bad when you size them up, like you did with that image. Second, you might work more through with your shading. Shading is really hard with a normal school pencil (which you probably used), but try pulling your strength when colouring dark areas, and be gentle in areas you want to light up. You can use your eraser to light up your shading, too.

Here's an example of an image I made recently. It's drawn on and fills an a4 paper.



Not that I should brag, but I thought it might give you an idea. =P