How I shade: (I use paint.net)
1. create the object with no shading
2. Use the colour picker to get the colour i want to start with
3. Make it lighter by clicking window then colours.
4. click more
5. slide S or V to make it lighter
6. Apply to object closest to light source
7. Slide S or V to make it a couple shades darker
8. Apply beside the part closest to light source
9. Repeat 7 and 8 until it is completely shaded
__________________________________________________ _______
Goomba