No picture here, but first things first. Measure the window to be covered. Measure to the outsides of any moldings so the whole window will be covered, then double your width to make sure you have some nice drapey curtains. Lastly, add enough width to take into account the hem on both sides, and bottom, this instructable will add 5 inches of width (four hems, two per curtain) and 3.25 inches in length (large top and small bottom hems.)
Go to the fabric store and pick a fabric you like. These curtains will be cut so the "grain" or warp is running top to bottom, so make sure the fabric bolt is at least as wide as each curtain you want to make. Buy enough yardage to accommodate all your curtains. I bought 4 yards of 48in wide fabric to cover 2 50in x 30 in windows and it worked out well.