(Answering old LJ comments tonight..haha.) I kept the squares straight by ironing everything, using my rotary cutter to cut the squares, and then I sewed the squares into strips. When I started sewing strips together, I ironed again and pinned at each seam. Carrie said once that if you have to have a pucker in the fabric, it's better to have it not at a seam because then people won't notice it as bad, so I tried to keep that in mind with my pinning. I didn't end up having any puckers anyway, so that was good. Also, I have a walking foot, which might have helped. I love my walking foot.