I've been doing a lot of cell shaded or mostly cell shaded work lately and my biggest thing is trying to figure out exactly what type of look I want. I've spent weeks rendering and rerendering and compositing and recompositing the same scene over and over trying to get it to look just right. I think I'm getting closer now. I had a thread going a while back of the project I'm working on now. I've actually changed rendering styles on it twice since then.