My Sweet Prairie: - Saturday Stitches - Colonial knot is a little different than a French Knot. It doesn't make that little doughnut. It makes a good tied knot by wrapping the needle in a figure eight.
Couching is simply sewing a heavy thread in place with a finer thread. It works beautifully by machine as well. I use a zigzag stitch to secure the heavy thread in place. And, if you have a cording foot— the foot guides the thread as you sew.