I’ve been stuck in Photoshop 7.0 for years, I’ve tried a few different programs over time and still find myself going back to 7.0.
My brush of choice is this one, which I use for both inking and coloring. I also use the default airbrush with no edits.
Oh hey I drew a little guide. Two steps.
1: New Layer, draw it. I try to avoid pure white, and instead use a neutral tone that fits the colors.
2: Layer effect - Stroke, with lower opacity and using a muted color within the scene.