If you want to be a writer, Michael says it takes a lot of practice, patience and perseverance.  He also says you should never be afraid to throw everything away and start over (which he has done may times).  In some cases, you will need to research your topic and find out as much about it as possible.  Then you need to take time to write a story that is clear and meaningful. 

Some children's book authors make the mistake of having stories that are too long.  Try not to have too many words.  Once you have written your text, you can either illustrate the book yourself, or find an artist to illustrate your story.  Most publishers can provide an illustrator if they like your story.   
 
When your story is finished, you then need to find a publisher.  This is the hard part.  There are hundreds of thousands of people who want to be published.  The competition is tough, and most publishers are very particular about the stories they want. 

You can check out a children's writer's market guide at your local library.  The guide lists publishers and what they are looking for.  You need to select the companies that you think will be interested in your work.  Check out their web site, or find books that they have published, and see if your book is similar to the work they produce.

And, if at first you don't succeed, try, try again.  Good luck!