<b>Make the swimsuit pattern and cut the fabric</b> Make one paper pattern 4 1⁄4-inches by 3 1⁄2-inches for the bathing suit and one paper pattern 1⁄4-inch by 8-inches for the strap. Cut out paper patterns.
Tug on the fabric to see which way the fabric stretches the most. Pin the pattern to the fabric, with the most stretch going along the longer side. Cut carefully around the pattern edges, and remove pins and pattern.
Pin the strap pattern to the fabric with the most stretch going along the long side. Cut around the pattern edges, remove pins and pattern.
<b>Make the swimsuit</b> With right sides together, fold bathing suit fabric in half so the shorter sides meet and sew 1⁄8 inch in from the edge, for the back seam. You will have a tube.
With right sides still together, turn the tube so the seam is in the center back. Sew a 1⁄2-inch line of stitching at the center of one open side to create the crotch, and leave holes for the legs. Turn bathing suit right side out.
<b>Finish the swimsuit</b> Try on doll and 1⁄8 inch down from the top edge, make a 1⁄2-inch-long vertical stitch at the center front; this becomes the bodice. Pull the stitch tight to gather fabric at the bustline. Stitch again over the first stitch to reinforce.
Fold the strap in half so it measures 1⁄4-inch by 4-inches. Pin the fold to the center of the bodice on the inside of the top edge. Sew the strap to the bathing suit near the bodice tuck. Put suit on doll and tie the ends of the strap in a bow around her neck.
This doll swimsuit sewing pattern is excerpted with permission from <a href="http://www.amazon.com/gp/product/0761154795/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0761154795&linkCode=as2&tag=craftfocom-20"> "The Fashion Designer's Handbook & Fashion Kit: Learn to Sew and Become a Designer in 33 Fabulous Projects"</a> by Marjorie Galen and published by Workman.