A. Measure the width of a tab-top curtain panel and cut an oblong scarf equal to that width plus 1 inch (you may need to piece 2 scarves together). Turn the cut edge of the scarf under 1/2 inch, press with an iron, then turn another 1/2 inch, press again, and machine stitch.

B. Cut sheer cotton fabric equal to the length and width of the curtain plus 2 inches. (If your curtain panel is wider than 45 inches — the standard for lightweight fabrics — piece widths together.) Turn 2 side edges under 1/2 inch, press, turn again, and machine stitch.

C. Join the scarf and sheer fabric by pinning, right sides together, along the long edge, and machine stitch. Press the seam open, then lay the scarf/sheer panel on top of the curtain, right sides up, and pin along the top edge.

D. Topstitch the scarf to the curtain.

E. Hem the sheer fabric.

Forty-four-inch-wide tab-top sailcloth curtain, $24, Pottery Barn, www.potterybarn.com. Sheer cotton fabric, about $5 a yard at fabric stores.