Here's how I've been painting my recent FGO pinups from start to finish. This is an easy method of shading that will instantly make your flat colors pop.

Thoughtfully done "painterly style" shading looks better in my opinion, if you have a good grasp on color and light (A good example is @hotGlossed on Twitter), but using the multiply layer is a fast method that I use often.

Also available in the archive (Folder: "Behind the Scenes")

$15 Patrons: Play around with the original layers in the PSD in the archive (Folder "2020"). Layers are all named according to this guide.