String piecing is a free-form quilt making method, so you do not need to mark a pattern onto foundations. Instead, you'll simply position strips, sew a seam, flip the strip right side up, and then add another. It's rather simple, but there are so many ways to string piece that the results are never boring.
String quilts are named for the strips of fabric that are used to make a quilt: the strings. The strings are sewn to a permanent foundation, such as muslin. You can use another fabric for the foundation if you like, or a thinner material, and even prints, but choose something that won't show through the strings after the blocks are assembled.
Tip: If you sew strings to a printed fabric, flip it over and sew on the reverse side, which is usually more subtle and less likely to be visible in the finished quilt.
String quilts likely originated as a make-do technique created by budget-conscious quilters because the method is a perfect way to use leftover scraps of fabric. The technique is still a great way to use quilting scraps, but today's quilters often purchase fabrics just so they can cut them into strings.
String Quilting Tips
Strings needn't be straight strips of fabric; cut some with angled edges to create variety. Strings needn't be straight strips of fabric; cut some with angled edges to create variety.
Don't worry about fabric grain placement, because the strings are permanently stabilized by the foundation.
Forget about trying to match fabrics. String quilts are charming when assembled from a wide assortment of colors and fabric styles.
Choose quilting fabrics in many color values.
Strings can be any width, and for the most interesting results, their widths should differ. Try cutting strips that are 1 1/4″ to 2 1/2″ wide for 8″ or larger blocks. Cut narrower widths for smaller blocks and miniatures.