I know the feeling. Making friends after that awful time ... now they're so very precious to me
They may be a bit overprotective ... but to me, they're my little children that I have to protect as well.
What I did (in mouselandia and SAI) was select an area I want to work on, like a limb or a shirt, then use either airbrush or a normal brush and paint in the shadow then a highlight after. I try to imagine the source of the light then see if I can actually shade the parts I want to shade in.
Unrelated: More torso goodness
I might need to use a mantra or mandala or something for this one as well ... it lacks ... more red.