Here's something that may help you in getting your 1/4 inch seam right. Measuring from the needle isn't always accurate because it doesn't account for the thickness of the fabric when you fold it open. Cut a couple strips of fabric 2 inches wide. Sew them together using what you think is 1/4 " seam. then press open and measure the two. They should measure exactly 3 1/2". If they are wider, then your seam allowance is not deep enough and you need to adjust it. If they are less than 3 1/2" then your seam allowance is too deep and you need to adjust it. Keep trying until you get a perfect 3 1/2" piece. Then double check by sewing 4 strips together. It should measure 6 1/2" exactly. When you get it right, mark it! Lots of good ideas for marking it. I've tried several ways and the best I've found is masking tape. Cut into the roll till you have several layers of tape. Unroll and cut off and place the tape where your fabric will butt up against it at that perfect 1/4" mark. I've been quilting for over 30 years and that is the one most important thing I've learned. Also, if you change the kind of fabric you use, (denim, flannel, wool, etc.) do this again because the fabric is thicker and you may need to adjust your seams again. I love making HST oversized and then trimming them to size with a small ruler that has a 45 degree angle marked. When sewing them, they always fit together so perfectly. Believe me, this took me a long time to learn to be accurate, but I wish I would have learned it sooner. If you are very careful to cut accurately and sew with an accurate 1/4" seam, your quilts will be beautiful every time!