The main market for preschoolers is picture books. These are usually 500-2,000 words. Most picture books that you will write for young children will be told in story form. They usually have beautiful, color illustrations that play a significant role in telling the story.
First you need a hook. Young children have short attention spans. You need a lead that will grab your reader’s interest immediately. Always have a theme sentence. Form this before you begin writing. Sometimes you won’t state the theme sentence as such in the body of your book, but it should be in your mind at all times. Don’t put anything in your book that doesn’t enhance your theme or is unnecessary. Every word must count. Write tightly.
The purpose of these books is for the parent to read them to the child, so keep in mind that you are selling to the parent. You have two to three seconds to hook that mom or dad. In the first paragraph, readers need to meet the main character who is doing something interesting. Every page must contain action. Each page usually contains an introduction, a body, and a conclusion. But occasionally you might have one word of text on a page for emphasis.
Then you will have either a list of topics to be covered, or a hint of what the book will contain. This is all general information. Then you need a transition. From here you move to the specifics of the points to be covered in the body of your book. Then back to the general with a summary and a strong ending. Be careful not to end the book abruptly. The child needs a concrete solution to the problem with a dynamic take-away message hidden inside. Now write a catchy title.