When you are working with an illustrator, one of the things you can ask for in your contract is a storyboard.
A storyboard is used to organize the text across the number of available pages of the book, and when an illustrator does it, they will have sketches of each page.
This way you can each see the author's concept of the book and iron out any problems.
You can see below one of the storyboards that my marvellous illustrator, Eva Morales, provided before getting to work on the full illustrations for The Big, Bad Bully.
I highly recommend including this in your contract with an illustrator. This way, there is no mis-communication for how you envision your book.
Sometimes the illustrator will misunderstand a small detail, and that will have a major effect on what the book looks like. For example, it may not be clear that your main character is in a different location.
That sort of thing isn’t always apparent in your text - especially if you are really good at staying away from narration and have the action moving with dialogue.
A storyboard lets you review it all before anything gets finalized - and that saves you money in the long run. Getting a storyboard is much more cost efficient than requesting re-dos of fully done illustrations.
I'm so excited, my first book is being redone early next year. You can see some of the storyboard that Eva sent me for I CAN Believe in Myself below. Jack Canfield is my co-author and will be adding positive mindset exercises.
This is one of the biggest perks of self-publishing. You get to choose who illustrates your story, AND you get to have input on how the illustrations turn out.
I’ve been truly blessed to be able to work directly with Eva for the books that have been, and will be, traditionally published. But, that is not normally the case. If you are able to land a traditional publishing deal, you typically have very little say on who illustrates your book, never-mind the storyboard and character concepts.