I apologize if my advice below doesn't address your problem. I was a bit thrown when you said that you'd "finished" a rhyming pb, but still need some help in writing it.
I'm sensing you're in a stuck place with getting everything to come together: rhyme, meter, meaning, and finding a way to make it funny and clever at the same time. I'm guessing that you've been looking at your manuscript for so long that you can't see it with fresh eyes.
If this isn't your problem, give us some more information.
The trick to creating rhyming books is flexibility. You have to try all kinds of different ways of saying things. In each verse, write the last line first--so you know the thought (and the rhyme) you're aiming for. Then let your mind run wild.
1. I think you're too concentrated on the end rhyme. Try using simple rhymes for the end rhymes, but maybe adding a clever twist or rhyme in the middle of the line. Here's just one simple example from my book THE SEVEN SEAS:
At first I had this--
So when I had to go to school
And study every map,
I knew I couldn't shut my eyes
And take a little nap.
Pretty boring. Here's the final version--a bit livelier:
I knew the rule that, when at school
And gazing at a map,
It wasn't wise to shut your eyes
And take a little nap.
Note the internal rhymes of rule/school and wise/eyes. The end rhymes are simple, but I added a little something in the middle.
2. Another trick--try coining a word or do some other kind of word play now and then. Again, from THE SEVEN SEAS:
The Red Sea looks like pizza sauce
A little or a lottle--
The roosters dine on ladybugs
With ketchup from a bottle.
You can't do this too often, but now and then--it's O.K.
3. Write verses in the morning when your mind is more flexible and you can think of more possibilities. People get into a perceptual rut. At least that's true of me. It really is easier to come up with ideas early in the morning--try it.
4. And, of course, check out lots of rhyming picture books from the library to see how other people do it. There are some good rhymers on this board, so maybe they'll chime in.
Good luck!