Mechanized Art

With everything turned to Normal at 100% opacity so you can see the actual colors used:

The short of it, from top to bottom (pixelated layers are irrelevant to the explanation because they're specific to this character design)

Top layers: Texture/adjustment layers (layer mode will vary)

Main highlight: Low opacity color blobbed over everything, typically centering around the face/chest of the focal character (usually yellow, but color will vary)

Body highlights: What it sounds like. I prefer using normal layers for this, the dodge layer modes are too "shiny" feeling for skin/most types of (matte) cloth.

Hair highlights: A low(ish) opacity glow dodge layer. They're done by taking the lasso select tool and drawing wave-shaped highlights, then slapping a gradient over them in the light direction.

Shading 2: Darker color, mostly to create faux line weight in corners where lines meet. Also to push back the farthest parts of the figure, e.g. the back layer of Aidan's hair here.

Shading 1: Main shade layer. Usually a light blue-purple unless palette dictates otherwise. Brownish-pink is partially airbrushed over the blue on skin (and some other warm-hued parts). Light pink is airbrushed along the edges on skin (and some other parts) to vaguely mimic subsurface scattering.

Soft Shade: Not always present. Low opacity airbrushed color that works something like ambient occlusion.

Flats Mask: Just dump some grey over the whole image and clip it to the flats folder. I just find it easier to mask out the flats sometimes. Not always present, especially if I'm doing something with a specific light temperature (warm sunlight, etc).