@LesleyCarol yup! And thank you 
One thing that I do a lot more now is to utilize 3d models for lighting. Magnus is a dragon and you probably won't be able to find a direct reference, but by piecing together references of a human body (he's pretty close), and a light source similar to where you want it to be, you can get a good ref and guess for where the light should be on your character itself.
Another thing is thinking in planes, which I learned a bit from @WeirdOwl . Since the scales make him extra angular, it was easier to think: ok this area is lit by the light, these faces are lit by the bounce, these areas are completely dark.
In accordance with thinking about light as planes, you also think of shadows in the same way. So the interaction between light and shadow shapes makes a piece interesting. I am pretty good at guesstimating cast shadows and grouping my values now, so being able to balance those also helps boost your general lighting.
I think in general though, the best way to get better at lighting is to get better at values management, and to get better at value management, I would suggest trying to do two-tone and three-tone paintings. Since lighting is such a big part of the composition, it kind of ties into that.
Essentially, you use black + white (two-tone), or black + white + 1 shade of gray (three-tone) to try to illustrate a composition. This is where you start to figure out how you can lay out a composition with basic shapes, and then understand how they interact with each other. You want the light to tell a story so setting them somewhere interesting (in a direction, in the middle, etc) will dictate how each piece is lit.
Example 1: In Magnus the Maker, he's the Maker, so the emphasis is on him making stuff. I should make that bright. This is a character card, so I should also have a good portion of his face showing.
Example 2: In Summon the Treefolk, my top directional light highlights the face and silhouette of the tree dude. He's important and is in the name of the card. The summoning action is also important, so let's highlight and add some magic to the peeps summoning him at the bottom.
An exercise of the two-tone thing - here's something I did for a Brainstorm class:
We took movies and basically did extremely small thumbnails in two-tone shapes. This helps with composition and also figuring out how professional directions set their lights and shadows.
