Recognize that children's books, particularly picture books, are printed in multiples of eight pages. Therefore, your book should be in some multiple of eight. Most common is 32 pages, which includes title and dedication pages.
Divide your work into parts that reflect the number of pages you have to work with. Place these parts into your storyboard system, which might be a computer file or just a sketch on individual pieces of paper.
Work on each spread, or the two pages that face each other. In each spread, illustrations and text should complement each other in a visually appealing manner.
Study the text to determine what type of illustrations will work best for creating a particular mood.
Determine the main element on each page. Ask yourself if other information-more text or illustrations-might enhance the content of the story.
Examine the flow of a story with your storyboard. In addition to looking good, each spread should make sense on its own, plus complement pages both before and after the spread.
Keep your storyboard flexible so that it's easy to move parts around. A system that allows you to physically interchange pages allows you to see how your children's book would look organized in different ways.