Remove any cushions from the rocking chair by unscrewing the cushion from the frame. If the cushion is stapled in place, pry the staples loose from the rocking chair frame with a flat-head screwdriver or needle-nose pliers. If you are reupholstering your rocking chair, skip steps 2 and 3 because you will simply be re-covering the previous cushions with new fabric.
Create cushions from scratch if your rocking chair does not have cushions to upholster. Measure out the size of the cushion you want to create and draw your shape onto a piece of cardboard. For rocking chairs, cushions typically are on the seat and back of the chair. Trace your cardboard template onto a piece of plywood and cut around your shape with a circular saw.
Apply a layer of spray adhesive to the plywood and lay your upholstery foam on top. Cut around the shape of your plywood with a utility knife. Apply a layer of spray adhesive to the top of your foam and follow with a layer of cotton batting. Pull the batting taut over the underside of your plywood and staple in place with a staple gun. Cut away any excess batting around the staples.
Lay your fabric print side down on a flat surface. Place your seat cushion over your fabric, cushion side down. Pull your fabric over the sides of your plywood and staple in place with your staple gun. Pull as taut as you can evenly around the cushion to avoid having your finished project look lumpy or misshapen.
Attach your upholstered cushions to your rocking chair by drilling in place with wood screws. Cover any holes with wood filler and allow to dry fully. Sand down your dry wood filler as needed.