The layout was going so swimmingly, I decided to humble myself by taking a shot at the cover art today. It didn't go as horribly as it could have, although I didn't attempt human figures, and I am relying heavily on the old trick of making a large illustration in hopes that shrinking it down will make it look less rough.
I also basically traced--I took a sharpie and made a rough drawing of, say, a Pincushion on one piece of paper, then put the paper with the illustration on it over it and used the outline as a guide. I think that helped avoid a lot of errors of proportion, plus it precluded the temptation to draw an outline of everything.
The most challenging bit is definitely the human figure, which is the unfortunate Philippe Trang getting the crap knocked out of him. I couldn't get the outline right, so I finally took a picture of myself in the mirror flailing about the way I imagine he might. That helped, but it probably means that Philippe will have a much larger butt than the poor man deserves. Maybe if I could find a picture of, say, Fred Astaire being knocked over....