If you are making a quilt with various blocks, after the blocks are sewn, I generally square up each block so they are exactly the same size. Use a firm ironing board, too soft of pressing pad will distort the fabric. If you want to control fabric, it is best to starch and iron dry. Use a good starch like Niagra, (one that doesn't flake). Then when I sew my blocks together, I match the seams first. I stitch about five stitches across each seam I wish to match then check to see if I am happy with them. Once I am satisfied, I stitch the entire length easing and stretching if necessary so that the between the already sewn seams line up correctly. It also does help to use a walking foot to prevent the top fabric from schooching. Good luck with your venture.