If you use a cotton material, be sure & prewash and dry it so it won't shrink so much. I think if you have a satin stitch around it already, hand sewing is fine. I made patches for baseball caps, cut a little away from the satin stitch, fringed them, then zigzaged them onto the hat with same thread as the satin stitch. If she used the same thread, the hand sewing will not show at all.