Base colour, shading colours on 0.1 opacity, use ref to see where shadows should go and put them in-
Use a different layer for each part (one for the hair, one for the face etc.)
Your art is amazing how it is already!
It took me 4 ish years to get to the point I'm at now-
I only started doing digital art close to the start of the pandemic lockdown and I found it really hard but I guess I'm used to it now-