|IIRC, I read this in a Nancy Zieman book. This produces perfectly even gathers. Cut a piece of clear elastic exactly the length you desire for the gathers (for example, the exact width of a bodice, front and back) plus two inches. Mark the one inch point on each end with indelible ink (the tails will be your holding points when you start to sew). Then, using the one-inch marks on the ends as the starting points, mark fourths, eights, or sixteenths (or even thirty-seconds) with indelible ink. Pin mark the skirt in the same increments. Pin the elastic to the skirt using the marks, with the one-inch marks as the starting and ending points. Secure them by sewing them down at the marks. Stretch the elastic from point to point and sew down around the skirt using a short zigzag stitch. The elastic will shrink to its original length. Then pin the skirt to the bodice and stitch together.