@MichaelaH I used the PDF list from the SVS class "How to Perfect Your Children's Book Portfolio" as a guide, and then created a personalised actionable list for myself.
I opened up a blank word document, and in it I wrote, for instance:
Toy Demon format: stand-alone illustration emotions environment (interior) kid creature Forest River Scaffolding format: double-page spread emotions animals environment (outdoors)This way I know what items in the checklist I'm able to incorporate into each portfolio piece. And then my next step would be to determine when I would finish each illustration, as @NessIllustration said.