One very important thing I've learned during the writing process is not to let your stories become sermons. Don't teach or preach to children in your stories. The idea is for your message to be relayed through the story itself and never in a direct way. Kids get enough teaching and preaching throughout the day, they don't need story time to be another time where they feel restricted by rules and lessons. Children learn best when they are taught in disguise.
You may notice that there are many stories where there are no parents at all in the story line. They aren't needed. Kids tend to learn from mistakes or accomplishments of others. The problem with sticking a grown-up in the story line is that it may hinder a character's problem solving skills by parental assistance. The lesson is for the child to solve the problem in their own way, without looking at the wise parent to fix it for them. How do adults know the answer?.... Well, at a young age they learned from trial and error. Author's must follow this rule to write successfully.
It is very important for writers to get in touch with their inner child. Relive the environment, emotions and lessons we learned through trial and error. It's a great approach to understanding how to best reach children through your stories.
Before you turn the page during story time, ask your child, "what do you think will happen next?" They usually answer, "I don't know." But when they come to a certain age, they may just give you a problem solving answer. That makes them feel smart and eager to read on. That's the outcome we love to see.