I like to base coat my rocks with a flat white spray paint...nice and quick. After I consult reference pics ..(usually via google's image search) I proceed with a pencil sketch. Then I lay my colors down light and watery to start. I've learned that for the white fur areas it's good to lay down a wash of blues/ grays before painting over them with white fur strokes. It helps give the fur more definition. I use light gray & light blue colors to make the fur strokes over the black fur areas. After I finish making the light colored fur strokes over the black fur I do a light watery wash of blue or purple over the light colored strokes to give them a tint. Another tip is to do a dry brush technique over areas of the fur...this helps make them look more soft and natural.