Mistakes & fixes

A knit hem that curls up on itself after stitching, refusing to lie flat, is caused by the fabric's stretch and the raw edge's tendency to roll. Stabilize with a twin needle and stay tape, or a coverstitch.

A jeans hem shortened while keeping the factory-finished edge and topstitching intact is done by folding the excess up inside the leg, then stitching just above the original hem from the right side.