I don't see what's so bad about your shading, the only thing is you should focus more on your light source. Start with one (or even 2 if you're more daring) fixed light points, and basically "see" your drawing as it would be in 3D. At least that's how I do it. Think of how it would be in real life so to speak, I'd have to make a big tutorial to explain it in detail, but it shouldn't be too hard. If you want any tips just ask, I'd be glad to help =D
Yeah, I have a looong way to go. I can't seem to fathom how shading's come so easy for other people. I can't seem to get the hang of it. But I'm trying. Really, I am.
Thanks so much! I'll try your advice out!