I’ve been working a lot with my partner, Eric Rohmann, lately. A few years ago, we came out with our first collaboration, Oh, No! Truth be told, we were a little worried about working together at first. Would we squabble? Try to impose our artistic vision?

As it turned out, it wasn’t terribly different from my usual process of working with an illustrator. I wrote a story, and he created illustrations for it. The best part was watching that magical process. Every day I’d head up to his studio...