Last month John Seerey-Lester came to campus and did a painting demo of a gorilla! As he painted, I did the same in my big sketchbook. He used acrylics, while I used watercolor. I was in an auditorium seat, so there was little room to paint, thus watercolor being my best option.
It was awesome painting with him, as I think the best way to learn art is to do it with someone; a guide. I learned a ton about foreground, mid-ground, and background. His method with acrylics is to start light with an underpainting, then continue getting darker. Once your values are close, you can use washes to push certain features back into the distance to create an atmospheric effect.
He signed my sketchbook, and is super nice! The best part is all the stories he has to share from being in the wild. It was nice to have a little entertainment while he painted. ^_^