🖌️ Glazing
Glaze means a paint that is meant to tint the whole applied surface evenly. Glazing is "applying a thin paint layer evenly on an area to change its color". You thin down your paint a lot and then apply only very thin layers. Or buy ready-made glaze paints.
Much like washing but you must have more control where you apply it. You can manually paint glazes into crevices but you use them differently compared to washes. Glazes are also frequently applied to subsections like "top-half" or "lower-half" to increase visual variety.
Glazes are better in creating shadows than creating highlights. Creating white with transparent paints is hard.
Try underpainting. One neat trick is to first shade and highlight with black, gray and white colors and then apply thin glaze layers to apply color.
Dark pigments make better glazes than light pigments. That is how it works.
Inks are excellent for glazing. They are much more transparent meaning that any dark colors will stay dark and not get colored by the glaze. Simply thin the ink a lot with water or a glaze medium.
Airbrush glazing is also a thing, and it is a lot faster with less control. For example, giving a hint of red to elbow to make it seem slightly bruised or apply a stripe of shine on metal.