The next interview I found is with Sarah Andrews, who is the art director at Meadowside Children's Books. What I found most interesting is that Meadowside is expanding into the YA market. Any expansion of YA fiction bodes well for all cover artists.
Q: What kind of content should an illustrator looking to attract the attention of Meadowside include in their portfolio?
A: I really love to see the process - a throw-away sketch can often be the start of a great idea! So it's useful to see as much as possible and it might be better for an illustrator not to spend months getting a single picture book just right, when (for instance) we might have a similar idea already in development. That time might be better spent working across a variety of ideas and projects, since just one drawing could spark something special or strike us as perfect for a text that's been waiting for an illustrator.
*sigh* I guess that means I should start sketching more. I haven't just doodled in my sketchbook, when I wasn't brainstorming a specific project, in what seems like years. It couldn't hurt.