Here's another one from the Malawi schoolbook "How Animals Move." The way I did these is that I did a tight pencil drawing, scanned it in, and cleaned it up. Then, so I'd have something to work with, I added flat color behind it:
My wife pointed out that the colors look very Dr. Seuss! That's why I chose this one to show the process.
Afterwards, I add all the details:
I'll be posting more of these soon. There were 7 books in all!