Since I tend to lay out a whole design before sewing into blocks, I have a lot of pieces to keep track of. I'd be afraid of just stacking the pieces as rows. So, I give each fabric a name and abbreviation (like NS for navy star), and record each one where it goes on a rough drawing. Then, I pick up each row in order, labeling the pile with a number on top. As I go, I name the fabrics out loud and try, anyway, to make sure the diagram is right. Sometimes the pile of pieces and the diagram don't agree, so I just skip over that part until later, so I can figure out which of the two is right. Or if either is.
I use the drawing again as I sew, putting in arrows for the direction of the seams, etc. I would be leery of keeping a whole pile of pieces in the right order without a backup plan.
hugs,
Charlotte