A broken seam is best repaired on a sewing machine. Working with the garment inside out, place a row of stitches along the seamline, overlapping the old stitches at the beginning and end of the break.
If you mend by hand, make small backstitches along the seamline; at the end of the break, secure the stitches with several small backstitches on top of each other.
If you cannot work from the inside of a garment, repair the break with hand slipstiches. Secure them with small backstiches. Tears in fabric
To machine stitch a tear, cut apiece of reinforcing fabric slightly larger than the tear and place this piece under it. Pull the torn edges together and pin and baste them to the fabric beneath; remove pins. With the garment tear side up and, using short, wide zigzag or multistitch zigzag stitches, sew over the tear. Use a fine needle, and match the thread to the fabric as closely as possible.
On medium-weight fabrics, you can repair a tear with iron-on mending tape. Cut it about 1 inch larger than the tear on all sides. Bond it to the wrong side of the torn area, following the manufacturer’s instructions.