Here's a sample from my newsletter.
From Picture Book Writing Tips:
Don’t lose touch with the little ones. The children are who you write for, remember them as you write. The shorter the story is, the better.
Read your story aloud. Rhythm and an easy read make the story flow and reading your story aloud so many times you get sick of reading it will show if it’s that extraordinary story or not. Why? You'll cut, cut, cut all the ugly out. What you end up with is the jewel.
Always give at least one sentence on why the thing the character wants is so important.
Make as much trouble for your MC as possible. Trouble, trouble, trouble and then when you think it can't get any worse make more trouble. Add that emotional pull.
Learn to think visually. Oh, and please ease up on the illustrator notes. The illustrator will have her/his ideas about the story. The story the illustrator sees will mesh with your vision.