Both turtles begin with a one minute sketch. When I'm painting naturalistically from photo references I'm thinking: "Light here, dark there, it's shaped something like this... That brush mark looks like..." and the form just happens. I use fewer colours when painting this way because a lot of the blending takes place on the wall. This turtle was rendered with 4 colours.

For simple shapes I really have to slow down. The shapes have to be crisp because the slightest wobble will show.
I have to be aware about the directionality of the brush strokes when filling in shapes. For solid colours that do not show the brush stokes, 2-3 coats are required, therefore it takes 2-3 times as long.
This turtle was rendered with 7 colours.