For this tree I used a photo for reference, although because it's a speed painting, I didn't put too much into making it accurate. I just sort of painted in a basic shape quickly to get a good composition and then went in with smaller round brushes and the darker browns to get some details with texture and shadow and the smaller twigs. Then with about 5 minutes left I threw in some highlights(I wouldn't normally jump that far ahead) just to see what certain areas of focus would look like.