Try for awhile drawing your 1/4" lines on the wrong side of the blocks. Sometimes a little prep work makes a world of difference. If you take the time to do this after awhile you will be so used to stitching that straight 1/4" you will not need to anymore. Careful pressing as you go along constructing your blocks helps with keeping them from becoming wonky. If you stitch a seam, press then find it is (off) it is much easier to fix right then instead of trying to fix the completed block