Picture Book process
While you will probably find basic similarities, the quirks of an artist's process are always great fun to see. (Below shows how I created picture book art for Edward Lear's poem, the "Owl and the Pussycat", for fun during a course.)
The very first step of any illustration project brief is to figure out what you are illustrating. In this case, a text, which was then broken into images or spreads.
My next step is to create lots and lots of lists. I list anything that I will need to draw or figure out, from environment to character and on and on. I also need to start thinking about mood here. This really directs how the rest of the drawings go!
Using the lists I created, I next work on finding the characters. And then, I work on emotions and posing, too!
I work on refining my thumbnails and page spread ideas to incorporate my character designs. And then refine and refine. I am also trying to pop in little items here and there from my lists.
I am putting cover design here, but honestly, I need to be thinking about this in Step Two as well. I find that the cover really helps me get in the right mindset for progress of the work. In the end, doing the cover work earlier can save me valuable time.
I follow up the cover and spread design with an actual spread colored sample.
Take a step back. Send off to peers/clients for review.
Work on comments. And now... move on to another project. Rinse and repeat, as some say!