Sand wooden furniture legs if there are wear or bite marks from pets. Put old newspaper on the floor, and wear a dust mask and cotton gardening gloves, to protect against splinters. Sand the furniture by hand with 320-grit sandpaper, sanding in the direction of the grain. Sand the wooden frame of the sofa next. Remove sanding dust with a tack cloth.
Turn the sofa on its side, and examine the frame underneath. Seal any splits or gouges with wood glue. Allow the glue to dry overnight. Sand the glued areas the next day. Stain or paint the sanded wood areas or simply coat them with a clear varnish to seal the wood. Prime the wood first if you are painting or staining, and apply two coats of paint or stain. Let the first coat dry before applying a second coat.
Measure the height, width and length of the sofa and sofa cushions. Write down the measurements and take them to a fabric supply store. Buy fabric in the pattern of your choice. If you aren't sure how much fabric to buy, ask a sales assistant for help.
Remove old sofa upholstery. Use upholstery scissors to cut the side of the fabric, and gently pull it off. Pull old staples out of the frame with a pair of needle-nose pliers. Remove old nails with the claw of a hammer, pulling up gently so you don't split the wood.
Attach the new upholstery fabric, starting at the back of the sofa. Staple the fabric to the frame at the bottom with a staple gun. Pull the fabric tightly, pulling it up and over the sofa to the front. Staple the fabric to the front and corners of the frame. Make sure the fabric remains smooth, not bunched in sections. Do the arms last. Cut off excess material, and staple the remaining material in place.