Remove the staples and upholstery tacks from the couch/sofa using needle-nose pliers.
Gently pull off the fabric from the couch/sofa to avoid tearing the upholstery because it will be used as a template for the new upholstery fabric.
Remove the batting from the couch/sofa's arms, backing, and seats.
Insert new batting into the couch/sofa's arms, backing, and cushions. Tack it down with upholstery tacks and hammer it into place with a rubber mallet.
Lay the old fabric on top of new fabric. Then cut around the old fabric, leaving 2 to 3 inches of overhang on all sides.
Place the fabric over the back of the couch/sofa and pull the sides tautly against the frame. Staple the fabric into the frame with a staple gun.
Drape the fabric over the seats of the couch/sofa and tuck the fabric under the frame, until tight. Pleat the seats and staples into place.
Lay the fabric over the arms of the chair. Fold the back of the fabric, the section closest to the chair's back, one-third of the way forward. Cut a slit in the middle of the fold and wrap the cut ends and around the arms, where the wood is exposed. Tuck any loose ends in between the frames and staple it securely in the same manner the previous fabric was attached.
Apply welting to the seams of the couch/sofa to add a decorative trim if desired. Purchase desired trim at a fabric store and fix it into the seams by applying small amounts of hot glue. Work slowly and in small sections to avoid staining the fabric. Work with a high temperature glue gun with heavy duty glue sticks for maximum adhesion.