@ScottGurley hello Scott! Im currently experimenting on how to learn lighting as well. I use watercolor as a medium and i found 2 color combo that work beautiful - a darker blue like indanthrene and warm yellow, this way its quicker than graphite.
I used colored pencils im the past but it takes time to fill in with color. !
What i plan to and that I recommend is to use a paper that already has a shade- like toned paper and use white gouache and some brown medium like ink for contrast