Start at the bottom edge of the recliner on the left side and measure up the left side, down the inner left side to the seat, over the width of the seat, up the inner right side and down the right side. Add 2 inches to this measurement for a seam allowance. This is measurement 1.
Start at the bottom edge of the back of the recliner and measure up the back, down the front of the recliner into the seat, across the depth of the seat and down the front of the recliner to the floor. Add 20 inches to this measurement for the seam allowance and to allow for the seat reclining. This is measurement 2.
Measure the width of the chair at the widest part for measurement 3. Measure the depth of the chair at the deepest part for measurement 4.
Cut a piece of fabric, fabric A, that matches measurement 1 by measurement 4. Cut a second piece of fabric, fabric B, that matches measurement 2 by measurement 3.
Fold the four sides of fabric A over 1/2 inch, then over another 1/2 inch and pin. Sew along the inside edge. Repeat with fabric B.
Drape fabric A over the recliner, from the bottom edge on the left side to the bottom edge on the right side. Push the fabric down so that it is flat against the surface of the recliner. Feel for where the recliner handle is on the one side. Trace around the handle on the fabric with the marker, then cut out along the traced lines.
Sew the raw edge of the traced cut-out with a zigzag stitch so that the fabric doesn't unravel.
Drape fabric B over the recliner, from the bottom of the back, over the seat and down the front to the floor. Drape fabric A over top of B, covering the recliner from side to side. You'll have a slightly misshapen "+" of fabric over the chair. Pin the fabrics together along the inside edge of the seat. Carefully remove the fabric from the chair.
Stitch along the pinned-together lines to join the two pieces of fabric. After sewing, drape over the recliner again.
Cut eight 8-inch pieces of ribbon for each side of the recliner, for a total of 16. Pin the ribbons to the slipcover along the upper back of the recliner. You want four pairs of ribbon on the left side of the chair and four pairs on the right side. Hand-sew the ribbon in place, then tie each pair together in a bow.
Sit in the chair and recline to make sure the cover is flexible enough to move when you lean back.