To begin with you have to sort the fabric pieces, I sort by size and I know that others sort by color. As I said in my post I also sort the fabric into Christmas, baby etc. Then the pieces should be ironed and squared off so that they are ready to sew together. You just pick a piece and find another one that is about the same size and sew them together, square off if necessary and keep on going with another scrap piece. It's so much fun and makes me happy to use fabric that otherwise would have gone into the trash or given away to another fabricholic. I have found myself asking others for scraps, think that might be dangerous.
I hope this helps. There must be pics of crumb quilts on the pictures part of this forum.