Visit your local library or bookstore and read as many board books as possible. Familiarize yourself with the genre and ask librarians or booksellers which types of board books are the most popular. Award-winning board books include Robert Salinatro's "My First Flip-Flap Book of Fruit" and Abdi Moshiri's "My First Slide-Out Book of Opposites."
Write your book. Board books are typically 16 to 32 pages long and include up to 300 words total. Each page should contain no more than 15 to 25 words. Use very simple language and themes that toddlers and preschoolers can understand. In terms of characters, young children are drawn to animals, toys and other children.
Send query letters to literary agents. Most major publishers will not review query letters by writers who are not represented by an agent, so you'll need to send agents one-page pitch letters regarding your work. Your query letter should include a summary of your board book and a brief writer bio. You can find a comprehensive list of agents and the types of work they represent in Writers Digest's annual "Guide to Literary Agents," available at bookstores and libraries.
Wait for a response from publishers. Once you've signed a contract with an agent, it might take many months for her to receive a reply from interested presses. If a publisher offers you a contract for your board book, your agent will consult with you and then negotiate the contract's terms for you.
Wait even longer. After an author signs a contract, publishers typically take one to two years to publish a book. Board books can take even longer, as they are almost always printed in China, due to the high costs involved in producing nontraditional-format books in the U.S.