I don't mark as my-ty does but I do trim before sewing on binding as I usually have quite the excess of backing/batting after sandwiching. I place my ruler 1/4" from edge of quilt and trim batting to that size then sew on binding. I use a 2.25" binding. I also learned it's much easier to not iron the binding in half. Line up the cut edge of my folding binding to the edge of the quilt and sew onto the front of the quilt. I then hand stitch to the back.