What works for me is that I shade using a low opacity color that is the "opposite" of what I'm shading, or something colorful. Like using blue or purple to shade orange, or pink to shade yellow, purple to shade red, and other colorful combos. Shading using gray can be a little boring, and shading with similar colors might not "pop out" as much.

I say shade everywhere on a different layer and erase where you think light is hitting lol try experimenting

I think I understand what you mean, Ill try to mess around with that a bit and see how it goes for me. Thanks for taking the time to help out ^^

Shadows have the faintest touch of blue to them.

Awesome tutorial on colour theory -> http://purplekecleon.deviantart.com.....rial-184642625

First of all, thank you for the very detailed note you sent me, I didnt understand some of the terminology at first, but I asked some people who know photoshop a bit better and they're helping me learn the interface. Also I checked out that link, and it was super helpful. It's so hard to find coloring advice that's easy to understand and actually explains color theory. (PS, the part about vomiting rainbows made me chuckle, seeing as how there are many pics on FA of furs literally doing that)
But all jokes aside, I really feel like I have a better understanding of coloring, Thank you for taking your time to help out ^^

Well, I don't know much about these programs myself, BUT, I what I do when I color by hand, if I want a realistic shade, I use either the same color, only several shades darker, or lightly color over a spot in gray[or black, or another dark color] untill it looks right to me. I also erase ALOT when I have a shiny or super lighted spot. I hope that helps a little?