My goodness, that's me too! I did 2 rows of a quilt, and one row was over 2 inches bigger than the 1st row. At first I thought I had the sashings different sizes on the 2nd row. But no - it was that one block was 1/2 inch bigger, one was 1/4 inch bigger, etc. And I thought I was being careful! Anyway, my problem was that I hadn't cut some pieces on the straight of grain and they stretched from me handling them. So I think cuttting on the straight of grain as well as starching would help. I was so tempted to put it all aside, but they're blocks we're all working on for one of my quilt clubs. I'm glad I fixed it.