Shading - at first I just cast shadows in different places to determine the main light source, and then I select a separate part of the character and make the shading clean and voluminous
Line and sketch - I am often too lazy to spend time doing a clean sketch first with a minimum of extra strokes X) Often a sketch and line layer is the same layer! My main tool when creating a line is a erazer. Yes, I just do as many lines as possible, and then I erase everything superfluous.
PS\ I'm trying to master screen recording, so I plan to post speedpaints soon at least for some specific moments of my working process