Originally Posted by CoyoteQuilts

I would starch and re-press first making sure I payed close attention to the seams. Sometimes I don't press each seam the best and that gives me wonky blocks.

Then I would re-cut. Here is a picture how to square up a 9 patch.
Cut 2 sides, rotate cut the other 2. See how the diagonal line on the ruler goes through the seams.

Does this help?