Since I’m starting to get ” how to” questions, I hope these pic that I’ve made will help. For shading I never use the dodge or burn tool, preferring instead to use smudging. With about 52% opacity on the tool I get a fairly sketchy look. To me it feels more like actual drawing that way. I used to until recently lay down the mid tone first, then add the shadow or highlight later. nowadays I start from the darkest. I do this by squinting at my subject and dividing the lighting into three layers.
when I need an inbetween color I take my brush tool reduce its hardness to zero, opacity to 34% and slowly add a bit of each color until I get the one I need. Its hard to explain, but if you look at my piece called Baklumps you should see an example of the technique in the corner of that pic.