You will need:
red velvet
red cotton canvas
braided piping
scissors
tape measure
chalk

Here's how:
1. Measure the height, width and depth of the headboard. Cut the velvet so the width is the width of the headboard plus 15mm seam allowance and 50mm for the hem. Cut the length so it's the height of the headboard plus 30mm for the seam allowance (15mm on both sides).

2. Make a mark on the back of the velvet to note the top and the bottom. The top is determined by the nap of the velvet. The nap should go up to the top, meaning when you run your hand along the selvedge, it's smooth.

3. Cut the canvas so the width is that of the velvet plus the depth of the headboard. Cut the length of the canvas so the length is that of the velvet plus twice the depth of the headboard.

To make the mitred corners of the slipcover, fold the canvas into a large triangle and mark the seam allowance and the depth of the headboard (two parallel lines) along with a perpendicular line from the fold.

5. Pin the cording to the right side of the velvet along the two sides and top, leaving an extra 10mm on either end. Sew it in place using a zipper foot.

6. Pin the cotton and velvet pieces with right sides together, and then sew them together.

7. Turn right side out and sew a double along the raw edges. Slide the slipcover over the headboard.