How to make a famous childrens book?
It's quite simple. Send it to a publishing company. (after rewriting it dozens of times) and if you don't get sent a reject slip, you're good! Authors have drawers full of reject slips.
First... write the book. Second... Make sure it becomes REALLY popular. If it doesnt become popular... it will never be famous. Be creative and put it on paper... that is all you can do.
Do you have a child? if so study the child listen to their wonderous and imaginative stories. you have to let YOUR inner child shine through