Here's a painting I did of my son Franklin when he was just four and a half years old. It's in oil, 6 x 8 inches.
I can't remember how I got him to hold still, but it's definitely painted from life.
Here's a closeup of the ear. I was using bristle brushes for most of the painting. The ear is stated in three passes/ three values. First there's a general skin tone scrubbed across the whole area, then a darker tone for the shadowed areas inside the ear, and finally a lighter tone for the planes catching the light.
One of the keys to painting a figure or a portrait is to think about such planes in groups. When I have a brush mixture for a given plane, I look for related planes and I try to define them before looking for new planes and creating new mixtures.