Cut fabric to fit your window. Cut two panels per window. The fabric width of each panel should be double the size of the window measurement plus 4 inches for hems. If you are using ready-made curtain panels, you will need twice as many panels as normal to get the fullness needed when pleated.
Turn under 1 inch for the hem on all edges. Turn under 1 inch again on the long edges. Stitch a straight line down the hem. Turn under another 3 inches on the bottom for hem. Stitch a straight line across hem.
Measure down 4 inches. Pinch together 3 inches of fabric, beginning about 1 inch from the hemmed side. Form the pinch into 1-inch folds or layers. Pin the layers together. Make 3-inch pinched folds evenly across the top of the fabric. Pin each set of pleats. Examine the appearance of the pleats occasionally by holding the fabric up. Pleats should be uniform in size and spaced evenly. Hand stitch along each pleat, a distance of 4 inches.
Fold 3 inches of fabric over the top of the pinned pleats. Stitch the folded area to create the sleeve for the rod. Repeat for other panels.