Figure out whether you want the curtains to meet, or puddle at, the floor. If you're looking to create a soft, romantic or Old World look, puddled curtains may be your choice. Curtains that graze the floor offer a more contemporary effect.
Measure the distance from the top of the window frame to the floor. If you choose to place your curtain rods 2 or 3 inches above the window, take the measurement from that point. To suspend curtains from near-ceiling height, place your measuring tape 2 to 3 inches below the ceiling and measure the distance to the floor. If you want the curtains to puddle, add 4 to 6 inches to the measurement. For example, if the distance from the top of the window well to the floor is 90 inches, add 4 to 6 inches to the figure to arrive at 94 or 96 inches for puddled curtains.
Measure the curtains for width, then double or triple that measurement to determine the correct size. A sense of fullness in curtain panels adds a sense of luxury to a space. If your window measures 60 inches across, for example, look for curtains that cover a width of 120 to 180 inches. Ninety inches across, or 1.5 times the window width, should be the bare minimum.
Install the brackets for the curtain rods. Standard brackets protrude from the wall by up to 6 inches and are typically attached via hammer and nail or screwed in with a screwdriver. Follow the package installation instructions in all cases. Small brackets that accompany some curved rods are practically flush with the wall; rods hook onto them via small holes at either end. Employ a level, or enlist a friendly observer to ensure the brackets are installed so the rod will be level.
Insert the rod into the curtain sleeve or loops until the entire curtain is suspended from the rod. Work slowly with sleeved curtains to avoid snagging or tearing the fabric on the inside of the sleeve. If you elect to use ring clips, slide the rings onto the rod first, then clip them to the top of the curtain at regular intervals.
Mount the rod onto the brackets and check the baseboard clearance. If your measurements were off and your curtains are longer than you like, you can hem them by machine or by hand.
Adjust the curtains so they hang in even folds across the window.