1. Interact with kids. If you have kids of your own, this is easy. You can also borrow your relatives' kids for the day. Talk with kids (with their parent's permission, of course) and ask them about their day, what they like to do, what they think of school, etc.
2. Remember the bullies from your school days. Schools are filled with bullies. Remember the ones you knew. Create character profiles of them, their traits, and make a list of things they would do and say.
3. Read as many children's books as possible. For parents, this is easy. Just read as many books as your kids will sit through. If you don't have kids, go to the library and talk to the librarian. Tell her that you want to write children's books, but you first need to study some of the popular books. Have her show you what kids are reading these days.
4. Keep a journal. Write about your memories from your childhood and key events that affected you. Write about your children's activities, things they did or are doing, the cute things they say, and write about the things that bother them, such as so-and-so not sharing.
5. Ignore the naysayers. There are plenty of mean people in the world that love to tear down other people's dreams. Avoid these people as much as possible.
6. Remember your childhood best friends. Create character profiles of each one. Write about what made them a good friend.
7. Observe the dialogue between children. Just kick back and listen to how they interact and how they speak to each other. Write down snippets of their conversations.
8. Study how to plot. Yes, even children's books are written from a plot outline. Take a few favorite children's books, such as something from The Magic Tree House or The Time Warp Trio, read through them and outline the plot. Learn about the 3 part act.
9. Begin writing down ideas. By this point, you might already have several plot ideas floating around in your head. Write them down so you don't forget them. Keep a list of ideas so that you will never suffer from writer's block.
10. Prepare to write. Create a work area for yourself. Create a schedule. Give yourself deadlines.