Determine the number of pages you'll have. Most children's books feature 32 pages, including front or back matter. According to the Writing for Children Workshop, front matter includes things like the title page, dedication page and copyright. Back matter may include author biography or list of references used. The actual text of the story most often begins on pages 5 or 7.
Draw the grid. On a single sheet of paper, draw a series of rectangles that are wider than they are tall -- approximately 3-inches wide by 1.5- to 2-inches tall. Use a line to split each rectangle down the center vertically to represent page spreads. A page spread is simply a pair of pages that face each other in a book. For a 32-page book, draw 17 divided rectangles.
Cross out the first half of the first rectangle and the last half of the last rectangle. Books always start on the right hand side of the page and end on the left hand side unless you're working in anime, which is reversed. However, the same principle still applies, so these two "pages" don't actually exist in book form.
Number the pages. Starting with the second half of the first rectangle as page 1, give each page an appropriate number. The numbers should be legible, but small enough that they're out of the way of your designs.
Label the front matter pages. This can be something as simple as printing the title of the book on the first page or simply writing the word "Title." Other pages can be similarly marked as "Copyright" and "Dedication."
Sketch out the story on the remaining pages, starting with the next odd-numbered page. This is not the actual book, so you don't need to worry if you are not an accomplished artist -- just get the basic concepts of your plan on the paper. The Advanced Computing Center for the Arts points out that beyond sketching and stick figures, you can also design your storyboard using photographs, stock images, clip art, or pictures from magazines by gluing them into place.
Use the storyboard to plan graphics so that they create a meaningful flow through the body of the book. You may wish to concentrate on consistency of image area, visual movement from one page to another, or creating a specific rhythm to your work. By having all of the pages in front of you at once, you will be in a better position to make these kinds of decisions.