The most important prerequisite is that you should have an obvious initiative about the age group of the readers, vocabulary, content and length of the work. The vocabulary used in books for four year old children's cannot be used in the books preferred for eight years old. Writers should be cautious to keep away from chauvinism and prejudice.
The children's story book should contain pictures and cartoons, so that it will be attractive. The length of the book should not be so long. In books for children it is important to have heroes and heroines with whom the readers can identify. The writers should know a child's taste before writing a book that is what types of stories and characters they love.
Dos and don'ts for children's writers
A children's writer should go to a library or book seller and should discover what types of books children's prefer.
The books should be written in a manner in which children's should enjoy it and also come to know about certain valuable manners.
Writers should learn to write a crisp, upbeat query letter that will grab the attention of the editor and the readers.
Before writing a children‘s book you should know the “rules of the publishing game.”
There are some restriction for writing a book, that is, what all contents it should contain and what all it should not contain. Mostly children's prefer comic books. If your story has a message then you should convey it through the pictures and characters hence don't use “moral” statement on the end.