Measure the width of the window. To determine how much fabric you will need for the curtain, multiply the width by two. Most fabric is approximately 45 inches wide. If your window 44 inches wide, you need 88 inches of fabric to cover the width. Buy this amount for each of the two fabric panels.
Starting at the top of the mounted curtain rod, determine where you want the curtain to fall. Measure the distance between the top of the rod and the curtain's resting place. Add six inches to this measurement to determine how long each curtain panel should be.
Calculate the amount of fabric you will need. For a 44 inch window that needs 45 inches in length, you need fabric to cover 90 in width and 51 inches in length. If buying 45-inch wide fabric, you will need four yards worth of fabric for the front of the curtain and four yards of another fabric for the lining. Cut into two panels, each will be 45 inches wide and 72 inches long.
Measure the width of the curtain rod. Record the information for later use.
Lay the panels of curtain fabric right side up on a flat surface. Smooth out any wrinkles.
Lay the panels of lining fabric right side down on the curtain fabric. Smooth out any wrinkles. The right sides of the fabrics should be together.
Pin the curtain fabric and lining together around the sides and bottom edge.
Sew around the three pinned sides with a 1/4-inch seam allowance. Remove the pins as you sew.
Turn the fabrics right side out through the open end. This will resemble a large pillowcase.
Press the large "pillowcase" with the iron so that the fabric pieces lay flat against each other.
Make a one inch fold in the top of the pillowcase, folding both open edges toward the lining side. Pin and stitch in place near the raw edges.
Fold the top of the pillowcase over again, another one inch also, toward the lining side. Pin and stitch in place near the fold. This gives the top a nice, clean edge.
Refer to the width of the curtain rod and add ½ inch to determine the size of the next fold. If the rod is 1½ inches wide, make a two inch fold. Pin and stitch into place near the edge of the fabric. This forms the rod pocket.
Measure and pin the bottom of the curtain to hem it to the appropriate size. Make a wide hem so the curtain can be adjusted if necessary.
Stitch near the edge of the folded fabric for best results, removing pins as you sew.
Slip the curtain rod through the rod pockets. The curtain will shirr on the rod because the width is twice that of the window.