Perhaps the easiest way to present the differences between a picture book, a first chapter book, and a junior novel is to show the same opening as it is appropriate for each. Taken from Gayle Roper’s Chapter 6 of The Complete Guide to Christian Writing and Speaking.
A Picture Book
“Don’t step in that hole,” said Dad. “I’ll fix it tomorrow. Let’s go play ball.”
I hit the ball and Jake chased it. Then it was my turn in the outfield. I heard something funny. “Listen, Jake. Do you hear that?” Two kittens tumbled out of the tall grass.
“Oh, Daddy,” said Jake, “Can we keep them?”
Andy, our collie, became the kittens’ mother.
One day the kittens were lost, and Jake and I couldn’t find them. Andy found them.
“Dad,” I said, “how do we get them out of the hole in the floor?”
All the missing details like where the hole was, what the kittens looked like, and where Andy found them would be obvious from the illustrations.
All the qualities that make good adult fiction make good juvenile fiction: conflict, suspense, pacing, focused plotting, complex characters, a strong beginning, a tense middle, and a satisfying ending.