To write a children's book the you want to start with choosing an audience and a basic story line. Right now publishing companies are looking for easy readers between ages 6 to 8, Chapter books for ages 7 to 10, and Spooky stories for ages 8 and up. You will want to stay away from cliches and stereotypes. Of course add more pictures for the younger group and less for the bigger kids. After your ideas are down, run them by a few friends and co-workers. Accept any constructive criticism as just that, constructive. Then it's time to find the right publisher and submit your manuscript.