My suggestions are to use a walking foot to sew the binding on. I do not press the folded binding first because when I stitch it on the back the top side needs a little extra fabric than the sewn side (hope this makes sense) For the mitered corners ==sew to 1/4 inch of the end,sew backwards off the binding, then fold the binding up and then fold it back to the new side and start sewing down that side. Just a few times and you will be an expert.