You hear it all the time, "don't write your picture book in rhyme." That's because many writers don't do it well. The story suffers to fit the rhyme; rhyme is forced; rhythm is off; there is no story.
I thought it would be fun to look at the openings of some recent rhymers.
HENSEL AND GRETEL: NINJA CHICKS by Corey Rosen Schwartz and Rebecca J. Gomez
Once upon a menacing time
two chicks knew a fox was at large.
Their Ma had been taken
and Pa was quite shaken
so Hensel and Gretel took charge.
First line does not rhyme, 2nd and 5th rhyme and 3rd and 4th rhyme. It sets up a pattern that the reader will expect. The same pattern is on the next spread. There's a fun twist in the old "once up a time" by adding the word "menacing." Again, we see a problem, and it feels humorous, so we expect humor to follow.
SNAPPSY THE ALLIGATOR (DID NOT ASK TO BE IN THIS BOOK) by Julie Falatko
Snappsy the alligator wasn't feeling
His feet felt draggy.
His skin felt baggy.
His tail wouldn't swish this way and that.
And, worst of all, his big jaw wouldn't SNAP.
Only two lines actually rhymed. Although the last two were "near rhyme" which some editors will not allow. But look how we see the Snappsy has a problem. Kids relate to not feeling that great. SNAP in all caps sets us up to expect fun language, and of course, there's obvious humor.
A DARK, DARK CAVE by Eric Hoffman
The pale moon glows
as a cold wind blows
through a dark, dark cave.
Those words are split across multiple pages. The pattern of rhyming two lines and ending with a dark, dark cave continues. This sets a mood. The reader is set up for something a bit spooky or mysterious in only 14 words.
In all three of these examples the writers are leaving out what the illustrators can put in.
They also used language that is kidlike. And there is rhythm. But most importantly there is story. Intriguing story. Picture book author Josh Funk says, "Story is most important. Rhyme, frankly, is least. More important, but sometimes less emphasized (pun intended), is Rhythm." For further reading go to Lesson #9 "Rhyming is all about Rhythm" in Josh Funk's Guide to Writing Picture Books.