This is an incredibly easy project. Simply cut 12" x 12" squares and sew with right sides together with 1/2" seam allowance, leaving a 3-inch opening on one side. Turn the napkin right side out, iron, and top-stitch with 1/4" seam allowance.
Cotton Woven (quilting cotton, flannel, etc - fat quarters work well)
Terry Cloth (can use a towel, but keep in mind that thinner terry works better)
I tend to make 6 at a time, but you can make as many as you desire. This is a great project for showcasing beautiful fabrics without needing a lot of material.