Make a kraft paper pattern by tracing the headboard (add 1/2 inch to the top for seam allowance and 3/4 inch to the sides and bottom for hems).
To accommodate the headboard's thickness, cut a strip of fabric the length and thickness of the top of the headboard. Add 1/2 inch to each long side for a seam allowance and 3/4 inch to the ends for hems.
With right sides facing, pin the front panel to one edge of the strip. Sew, using a half-inch seam allowance. Repeat with the back panel and the other edge of the strip. Press seams open.
Hem the perimeter of the entire slipcover: Turn under 1/4 inch, and press; turn under again 1/2 inch, and press. Then stitch along the entire perimeter.
You will need to make eight tie tabs for one headboard. For each tab, cut a strip of fabric 9 inches long by 2 1/2 inches wide. Fold the strip in half lengthwise, with right sides facing, and press.
Using a 1/4-inch seam allowance, make a fabric "tube" by sewing along the entire length and along one short edge of the strip.
Trim the seams, and turn the tube right side out (a chopstick can help you with this task). Press.
Pin the unfinished edges of the upper and lower sets of tie tabs to desired locations on the slipcover. Sew the tabs to the cover, turning under the raw edges before sewing; drape the slipcover over the headboard, and tie the tabs together.
A simple fabric cover refinishes an old wooden headboard (and footboard) without requiring any scraping, sanding, or painting. Choose heavyweight fabric for this project; it works like instant upholstery, softening the lines of the wooden form underneath.