On lighting barley use white it will turn out bad just use the same coler has the body part your lighting up to light it up.

Uhm well.. I just use a low opacity dark red for darker shading and a low opacity white for light shading. Also you need to know where the light is coming from in order for the shading to look good I guess. Is it coming from above? Below? The right or the left? When you know where the light is coming from then you can start shading it in. Well at least that's what I do.

I just use grays, lighter colors you only use little bit from the middle color of both light and dark. too much will make it TOO light. Same to go with shading. It gets it all done well as long as the lighting and the shading looks presentable. Or you can construct your own away to shade and light :V