Sewing the perfect 1/4" seam is the most common sewing problem I have seen in all my years of quilting, teaching and being around other quilters. For years, I wasn't careful and I would ease and stretch to match up my seams. I have finally mastered that darn 1/4" and my quilts go together so much better now, I wonder why I didn't work harder at it years ago! Take three short 2" strips and sew them together using what you think is a 1/4" seam. Then press seams to one side and measure the center strip. If the center strip measures a perfect 1 1/2" then you have a perfect 1/4" seam. If not, adjust your 1/4" seam. When you have it perfect, mark it! I used a blue marker and then used painters tape, cutting a section out through several layers of the tape. I place the tape along the line that I marked on my sewing machine, to guide my fabric through. The only other thing you need to be aware of is to be very careful of your beginning and ending. It's easy to let go of your fabric before it is all the way through the foot and the seam will veer off, making the end either wider or narrower than 1/4" . Once you get this accurate, your blocks will go together so much easier and your seams will always line up perfectly! And be very careful to cut accurately!