I adore the work of Mem Fox. She has a great web site with some really useful information for writers.
This is particularly good information and smacks of experience.
While this is aimed primarily at picture book writers, I think all children's writers should heed most of this advice.
The tidbits I am particularly drawn to, though, are the ones about rhythm, like these two:
DO NOT assume that plot is the most important element in a story, or even the only important element in a story. Character comes first. Next comes the precise choice of words and the correct rhythmic placement of those words. Then trouble…
DO NOT forget that the rhythm of the text is the element which will, or will not bring the reader back to the story again and again.
For me and my writing style, rhythm is critical. I know when it's on track and I know when it's off.
The way the writing sounds is as important as what the writing says.