Sewing Tip: Iron your topstitched seams to release stitch tension and achieve a smooth professional finish.
As soon as you complete your topstitching application, iron the seam in the direction the stitching was applied. Since you'll be ironing directly on the fabric's face side, be mindful of heat sensitive fabrics. Set your iron to the highest heat setting appropriate for the fabric at hand. If working with fabrics that are damaged or stained by the iron's sudden excessive heat, use a protective cotton cloth between the hot iron plate and fabric layer.