Measure the height of the chair back, from the seat to the top of the chair.
Measure the width of the chair back at the widest part.
Draw a pattern on the tissue paper, using the measurements taken. These lines will be your stitching lines when assembling the slipcover.
Draw a line 1 inch outside the pattern you’ve drawn. These lines will be the cutting lines.
Match the selvage edges of the fabric to fold it in half with the right sides of the fabric together.
Pin the pattern to the fabric and cut around the cutting lines to make two slipcover pieces.
Remove the pattern, replacing the pins as you go.
Stitch around three sides of the fabric, using a 1-inch seam allowance.
Trim the seams to 1/4 inch.
Fold the open end up 1 inch toward the wrong side of the fabric. Fold the raw edge back, sandwiching it between the larger piece and the folded edge.
Stitch around the opening of the slipcover, running the stitch line along the two folded edges.
Turn the slipcover right side out and slide it over the back of your chair.