As the client has made her selection of the pose and composition she prefers, I begin cleaning up the thumbnail by placing tracing paper over the initial sketch and overlaying rough perspective lines in blue. I cheat a little on the perspective as it's not necessary to be 100% accurate for this piece so I don't bother agonizing over lines being a little off. I've been told that as long as it looks correct, it is correct - at least to the viewer. Mind you, in something more obvious, I would take more care. I follow this by outlining the shapes of the character in red so as not to get mixed up with the perspective lines drawn. Something else I learned is that it's easier to work with perspective on a thumbnail or smaller picture than at full scale and having to break out the extra long rulers! ;-)
Once happy with the layout, I outline the cat and bed in pencil and add some light shading. At this point, I scan it in and bring it into Photoshop for inking which I do on a separate layer above the scanned image.