We start where children's books always start: the manuscript. This is the idea that we have to flesh out with artwork. Find out what a professional manuscript consists of, and tips for working with them.
Being able to tell a story is at the heart of this medium. But it's not just visual. You have to work with the text and make sure that what you are creating is adding to the manuscript, rather than simply being redundant.
I once had to update an 80s character design to something more contemporary. Here are the principles I used and thoughts about shapes, character design, and posing that will help your work fit in today's media market.