Tear-away clothes are not just for strippers. A ragged dress can be torn away to reveal Cinderella's ball gown. They will speed up any theatre quick change. Warm-up trousers that open on the sides allow an ice skater to remove her trousers without taking off her skates. But they're also useful if you want to quickly reveal your shapely legs.
Add 1 inch to sides of the front and back of your trousers pattern. Cut out the trousers.
Iron down 1 inch on the wrong side of the fabric along side edges.
Construct the trousers according to your pattern directions, but don't sew the side seams.
Sew 2-inch lengths of hook-and-loop tape along the folded down fabric on the side edges, leaving a 1-inch gap between the pieces of tape. Sew the tape on by sewing along both edges of the tape with a straight stitch. Place the loop on the outside of the trousers on the back edge and the hook tape on the inside on the front edge.
Pin the center back of your pattern pieces 1 1/2 inches away from the fold in the fabric. Pin the center back of all back collar pieces the same distance from the fold.
Cut out the pattern.
Cut the back of the garment and all collar pieces along the fold in the fabric. Iron down 1 inch on the wrong side of the fabric on the back pieces along the cut fold.
Construct the shirt or dress according to your pattern.
Sew 2-inch lengths of hook-and-loop tape along the folded down fabric along the back edges, leaving a 1-inch gap between the pieces of tape. Sew the tape on by sewing along both edges of the tape with a straight stitch. Place the loop on the outside of the shirt or dress on the right edge and the hook tape on the inside along the left edge.
You may skip making a fly in tearaway trousers because you can put them on by fastening the tape on the sides. If you have enough fabric, you may pin the pattern pieces for a shirt or dress 1-inch from the selvedge edge. This will give you a finished edge to work with and you will not have to cut along the fold.
Tear-away clothes require more fabric than regular clothes. Buy the amount of fabric recommended for the garment two sizes larger than the size you're making.