A tone painting of a drawing of mine. This is about a half hour compressed down to a couple minutes. I've been trying to post a couple videos of things people want like the finish shading on a drawing and current color method for digital painting but they're still not working out so maybe this will be of interest while you continue to wait. Sorry.
I put the drawing on it's own layer set to multiply, on the base layer I use the paint bucket to apply this greenish brown tone. Then on a layer in between those two I do my painting.
Always follow the general to specific rule. I start out with broad brush strokes defining the overall values then work down to more specifics. First adding darks and when those are getting close I add some lights. Most of the painting is done with the base tone, a 70% dark value then a 30% light value. Only toward the end I will start to use the colors within this range. And at the very end, real bright and darks values to pop specific limited spots.
Hope that helps.