Well, personally I learned from observation and curiosity, I think those are the most helpful tools. NC Wyeth and Sargent's non-portrait works were very instrumental in helping me recognize those effects in nature.
But if you're looking for an instructor, I strongly recommend James Gurney! Has an excellent blog [link] with a lot of really helpful entries, but to get his best stuff you'll have to (though it's far from a chore!) read his books: [link] and [link]
This is a really nice tutorial. And a good spot with the random blues. I tend to use light and reflection, refraction and deflection etc for it'e eye catching and eye guiding abilities and influencing mood / theme. I stay away from overly realistic lighting (because I can in a drawing) but confuse the eye into doing what I want. You're great at doing that yourself. I've been an admirer of your painting for a while now. And I can definitely see Wyeth's influence on your work. Very nice indeed.
Guilty as charged. Fact is, that blue (or orange) light just works so well for cheaply emphasizing volumes, especially in cheesy, dark fantasy pictures where realism be damned. But I'm more fond of drawing things that make sense (even if not 100% realistic), so I really appreciate this. It's actually amazing how much brightly coloured clothing DOES reflect off skin for instance, and you hardly ever see that in art. One day I was walking around specifically looking for reflected light and it struck me how much of it there is in real life, especially in warm summer days. We're just somehow really good at ignoring it *pets light* It's ok, I like you!
You give great advice. I especially appreciate your notes on light and color (I also liked the thing about kids shapes- but I'm extra fond of the color tips). You are just brilliant with color, and there is so much to learn from your process.