Making a valance from a pattern involves taking measurements, cutting and pinning the fabric. The next steps include adding the pleats, hemming the ends and sewing the fabric.
To make a window valance from a pattern, measure the window rod including around the curves. Add roughly 5 inches to the length to accommodate pleats. Also measure and cut the desired length of the valance, allowing 3 inches for seams and for the rod casing.
Next, lay out the fabric along the length of the curtain rod. Make sure it's centered, and make a vertical mark for where the pleats should go. Start by measuring in approximately 4.5 inches from either end, and then mark pleats in between. Use the vertical mark as a guide to fold in the pleats with the mark in the center. Baste across the top of each pleat.
Roll up the bottom of the valance 1/4-inch, and press. Repeat this process, and sew in place. Roll down the top of the valance enough to easily accommodate the curtain rod with 1/4-inch hem allowance. Roll under the hem, and press, Sew the pressed edge of the hem to the valance to create the casing.
Roll either end of the valance in 1/4-inch, and press. Repeat this procedure, and sew in place. Hang the valance.