Becky,
My mom-in-law used to make string quilts. She used a muslin or old clothes square about 12x12 and sewed strips of scrap material on them at a diagonal. The strips varied in width, even from one end of the strip to the other. Start in a corner by placing two strips right sides together, at the corner, and sew a seam. Trim the excess in the seam if needed, and open the fabric. Then, sew another strip to the block, right sides together, open that, and continue until block is covered. Then, trim the block back down to a 12x12 square. She usually set them in a zigzag pattern. It goes fast, can use any leftover fabric at about any width from a "string" up to about 4 to 5 inches. She usually tied them rather than quilted. I still have one she made.