An easy way to make a dust ruffle is to use a fitted sheet. Cut a strip of fabric that is triple the length and width of your box springs. The strip should be 12-15" wide depending on the distance between the top of your box springs and the floor. With the longest stitch on your machine, sew a long basting stitch around the top of the strip. Pull threads gently to gather the fabric evenly until it is the right length to go around your box springs. Sew this strip to the bottom edge of a fitted sheet and you're done.