I do mine all by machine and first stitch it on the front, press the binding away from the body of the quilt, then pin it to the back. I stick the point of the pin in very close to the edge of the binding FROM THE FRONT OF THE QUILT!! I'm not yelling...I'm just emphasizing. How do I do it? I feel the edge of the binding on the back with my fingers and get the point in as close as I can to it...then..I stitch it from the front. I can see to make my stitch line parallel to the original stitch line and because I see where the pin went into the fabric, I can ensure that my new/second stitch line is capturing the binding on the back. I also sometimes use a decorative stitch for this second seam, doing the pressing and pinning the same way. Works for me every time. If it's a bad day for sewing but I want to keep on..I add an eighth or an quarter inch to my original cut strip so that I have a little extra on the back to help ensure I catch it in the stitching. Truth is, it's so much easier with the extra width that I frequently do it even on good sewing days.