Step 4. Fold quilt on diagonal, right sides together. Align border strip raw edges, border seams at the 1/4" backstitched point, and creases; pin in place. Stitch along crease, backstitching at 1/4" border seam.

Step 5. Press seam open. With quilt right side up, align 45 degree angle line of square ruler on seam line to check accuracy. If corner is flat and square, trim excess fabric to 1/4" seam allowance.

For multiple mitered borders, sew strips together first and attach to quilt as one unit.