Use twill tape in your stitching, when seams require stability or reinforcement. Twill tape is a woven ribbon, often made from cotton, that comes in a variety of widths and colors. Whether you use twill tape to stabilize seams or to construct a casing on the inside of a garment, it is suitable for many different sewing projects.
Cut the fabric pieces to the correct size, following the instructions and patterns. Find a seam to sew that needs stabilizing -- often a neck or shoulder seam.
Cut a length of 1/2-inch-wide twill tape, about 2 inches longer than the seam.
Pin the twill tape to the underside of one of the two fabrics being sewn together. Align the edge of the twill tape and the edge of the fabric, at the point where you will sew the fabric pieces together.
Adjust your sewing machine stitch to about 3.0 stitches per inch and sew the twill tape to the fabric, using the seam allowance recommended in your pattern instructions. Remove the pins.
Pin the two fabric pieces together, right sides facing each other, with the twill tape on the outside edge.
Adjust the stitch length back down to 2.5 stitches per inch and stitch the seam. Remove the pins.
Trim any excess twill tape so it does not extend beyond the fabric on any edge.
Measure the length of casing you require with the tape measure. Cut a length of 1-inch-wide twill tape this length.
Position the twill tape over the fabric where you want the casing. Pin the twill tape in place.
Stitch the twill tape casing in place, by sewing along each long edge, about 1/8-inch from the outside edges. Leave the ends unsewn. Remove the pins.
Insert elastic or a drawstring into one open end of the casing and work it through until it emerges out the other end.