Grunt guy

I actually doodled this grunt on paper at work ages ago while I was installing something. I finally got around to drawing it semi-properly. I tried to aim for something that hides a lot of the detail in the shadow and looks a bit like a futuristic knight.

On another note, does anyone have any good tips on shading? I find either there is perfect smooth shading like a 3D image, but that seems too hard for me, then there are other techniques that just layer a couple of shades but then it ends up messy as in this picture. I don't know how to do either method 'properly' so any tips and help or pointers to some tutorials would be much appreciated.

Thanks.