Remove existing fabric from your sofa as gently as possible. Pry away any staples with the flat edge of a screwdriver.
Repair the couch wherever necessary -- by adding new foam, tying springs with jute twine or using wood glue to replace any broken pieces -- before covering it with new fabric.
Drape pieces of muslin cloth over the various sections of the sofa that you want to cover. Trace out the shape of the back, inside front and arms of your sofa. Check for symmetry by folding the pieces in half and matching up your lines as needed.
Add 1 inch of extra length to each side of your drawn pattern. Cut out your pattern pieces and position them over your new upholstery fabric. Pin the muslin to the fabric and cut around the pattern sides. Fold the extra inch of material underneath the fabric and press the folds flat with a hot iron. This will work as a hem for your upholstery pieces.
Cover the back of your sofa. Position your back fabric piece in place, pull it taut, and staple the piece directly to the couch frame. Continue in this manner on the inside front of your couch and then the arms.
Walk your fabric slowly around curved areas and corners, stapling tight and in straight lines as you go along to keep the fabric as flat as possible. If the fabric bunches too much and is difficult to smooth, you may need to cut small slits to help the fabric fold over itself more cleanly. Try to staple on the underside of the frame or in places where the staples are not visible. You can also cover the staple line with piping that you hot glue in place.
Remove cushions from the sofa. If possible, remove any fabric currently around the cushion. If the fabric is still intact, remove it as delicately as possible so you can retain it as a pattern for your new upholstery fabric.
Replace the cushion foam as needed with a layer of cotton batting wrapped around 2-inch upholstery foam. This is an important step sometimes overlooked by home upholsters -- and is your strongest defense against a lumpy and misshapen couch.
Lay your new upholstery fabric flat on a surface, print side down. If you were able to retain the previous material to use as a pattern, trace out your fabric pieces. Otherwise, lay the cushion directly on the fabric and double the fabric over the top. Pin it in place and trace out the shape of the cushion onto the fabric.
Cut out your fabric pieces for your cushion and sew three sides, print sides facing in. Turn the fabric right side out and insert your cushion. Sew the back of your cushion closed with your machine or by hand.