Each serious profession has their own professional organization -- a group that most all serious members of that group belong to in order to be considered seriously dedicated to their job.
Librarians have a professional organization called The American Library Association. And there are local groups at the state level. Both hold conventions to aid in the continuing education of the group.
Chemists have them, engineers have them, teachers have them.
And so do writers.
If you are seriously determined to be a writer, to become a better writer, you join your professional organization. And the professional organization of Children's Book Writers is the Society of Children's Book Writers and Illustrators (because both kinds of artist are necessary to create these books), also known as the SCBWI.
Here's one person's ODE to the SCBWI -- 15 reasons why I Love the SCBWI, written by Joanna Marple over on her blog, Miss Marple's Musings.
Follow the connections there if you too are interesting in being considered a professional writer.