Yes!!! DO PRESS and "square" up each block before putting them together.. Especially if you don't have a border/sashing going around each block. If you are still having problems with matching, then the problem is the size of your stitch width.. Is it 1/4 inch? or are you wavering as you sew.. Mark your machine with tape or use a 1/4 inch foot... Go slow and try not to rush as these blocks are gorgeous when added to each other.. but can be so frustrating matching those corners.