Remove the old cushion covers from the glider rocker. Use a seam ripper to undo the seams. Work carefully so you do not damage the fabric. You will be using the old fabric from the cushions on the glider rocker as a template for the new cushions.
Lay the new glider rocker upholstery fabric face down on a table or the floor. Pin each of the old pieces of fabric to the new upholstery fabric.
Cut the new upholstery fabric to size with a pair of fabric scissors.
Use a piece of chalk or a pencil to mark pleats in the new fabric. Pin the pleats in place with a fabric pin.
Pin together the pieces for each cushion or pillow. Sew the pieces together with a straight stitch, working with a 1/4-inch seam allowance on each cushion. Leave the back of each cushion open to reinsert the foam.
Pin together the two back edges of the cushion and stitch it together by hand with a blind stitch.
Place the finished cushions on the glider rocker.