I begin by painting the outlines of the characters; you'll notice that there is a light and a dark side to these lines determined by where the light source is coming from (see Hugo's ears). Then I block in the base colour of the animals as you can see on Billy's face. There are so many colours and tones used in each animal (let alone the backgrounds) that I have to keep a record of how I have done it in the other books. It's like walking in your own footsteps; hopefully along the way you think: 'This is a good choice; that guy knew what he was doing when he picked this colour mix'!