Measure the space you want to cover with your curtain. If you're measuring a window, begin measuring at the point on the outside of the window where the outer edge of your curtain will fall, and measure all the way over to the corresponding point on the opposite side of the window. Add 6 inches for side hems. Multiply this measurement by 2 to 2.5 for a loosely shirred curtain, and 3 for a more closely shirred curtain. Divide the total in half. This is how wide each curtain panel should be. Measure from the top of the curtain rod to the point where you want your curtain to end. Add 9 inches for hems. This is the length you should cut each curtain panel.
Cut out your curtain panels to the appropriate size, as determined by your measurements. Hem the sides and the bottom of the curtains. Turn under 1 inch of fabric, and press. Fold under again a second inch. Press and stitch into place.
Fold under 1 inch of fabric along the top edge of the curtain and press. Fold over a second time, this time folding over 4 inches of fabric. Press.
Measure 1 inch from the top of the fold at the top of your curtain. Mark this with a straight pin at each edge. Use tailor's chalk to mark this 1-inch line all the way across the top of each curtain panel. Sew along this line. This is the top edge of your rod pocket.
Measure the width of your curtain rod. Measure this distance from the line you just sewed and mark this second measurement with tailor's chalk all the way across the top of each curtain panel. You should have a line of stitching with the chalked line beneath it. Sew along this line. The space between the two lines is your rod pocket.
Slip the curtain rod into the rod pocket of your curtain. Gather the curtain on the curtain rod, smoothing and tugging the curtain with your hand to keep the shirring even.