Hi @mineopoly, nice to hear from you! I remembered another resource that was really, really helpful to me when it comes to lighting and shading. It's a tutorial series called "Landscape Painting Crash Course" by a great digital painter named Aaron Rutten. https://www.youtube.com/playlist?list=PLo_kbikcLfN-g0XcF48qyZfsE0xTkly3q
I watched a few of these in the couple of days while I was waiting for my tablet to arrive in the mail. The way he explains light and shadow was really simple to understand. Basically, shadows are cooler in hue (towards blue) and less saturated (towards grey.) Areas facing the light are warmer in hue (towards red) and more saturated (towards pure color.) Starting with that basic concept was very empowering for a beginner. Otherwise I think I would have been picking colors at random and not have a clue where to start!
Actually, I need to watch more of his videos and complete the series. It is so amazing how he talks about objects reflecting the colors of the sky, the ground, and other surrounding objects. He also helped me understand that there is often a glowing edge of highlights around the shaded edges that is reflected from the sky or background.