Measure for and Prepare the Fabric

• 1). Measure the width and length of the window. According to sewingneedlework.com, valances should be 18 inches long for the average window; one quarter of the window length is ideal. For these purposes, the window measures 45 inches wide by 72 inches long.
  
  
• 2). Do the math. Sewingneedlework.com suggests "double the width of the window when heavyweight fabrics are used and triple the width for lightweight materials" to make a gathered valance. There will be a 3-inch hem on both the top and bottom of the valance, which will add 6 inches for each hem. Because you need twice the window width (45 inches) to create a gathered valance and fabric most often comes 45-inches wide, 30 inches is half of what is needed. For this example, you need 1 2/3 yards of fabric.
  
  
• 3). Wash and dry the fabric if it is machine washable. If the fabric is prone to shrinkage, this will shrink it prior to sewing the valance. If the fabric is wrinkly after drying, it is wise to iron it to make it easier to work with.
  
  

Sew the Top and Bottom Hems

• 1). Cut the fabric. In this example, the fabric must be cut in half, leaving two pieces of fabric measuring 30 inches long by 45 inches wide. Because the factory-finished edge (also known as the selvage edge) tends to stay straight, fold the fabric in half while lining up the selvage edges to help create a straight cutting edge.
  
  
• 2). Iron and pin the top and bottom hems. Place the fabric right-side down and carefully measure 3 inches all along the raw edges. Fold the fabric at the 3-inch mark and pin the raw edge to the wrong side of the fabric to keep it in place. Iron the fold edge. Remove the pins, and then fold the ironed edge of the fabric over another 3 inches to create a double hem. Place the pins perpendicular to the fold on the edge that was first ironed to attach it to the main body of the fabric. Iron the new fold edge, and then sew the pinned edge with a straight stitch.
  
  
• 3). With the fabric right-side down, fold the selvage edges over, iron and pin the fabric just enough that it can be sewed to create a clean, finished edge. Sew the side hems.
  
  
• 4). Repeat these steps with the second piece of fabric.
  
  

Install the Grommets

• 1). Measure the valances to determine how many grommets to use. Thedecoratingcoach.com recommends dividing the fabric width by 7 when deciding how many grommets to use. For this example, six grommets would be necessary for each valance.
  
  
• 2). Lay out the valance to determine grommet placement. You want an even number of grommets on each valance, spaced approximately 5 inches apart. The grommets closest to the side seams should be located about 1 inch from the side edge of the valance. The remaining four grommets should be evenly spaced. All grommets should have an equal distance between the top edge and the top hem seam; for this example, the middle of the 2-inch grommets should be at 1 1/2 inches from the top of the valance.
  
  
• 3). Trace the inside of the grommets on the backside of the valances by holding the grommets in place using a fabric marker or fabric pencil.
  
  
• 4). Cut the fabric to create holes where the inside of the grommets will be.
  
  
• 5). Attach the grommets. Be sure to use the front grommets on the front side of the valance. Holding both the front and back pieces of the grommet in place, snap them together.
  
  
• 6). Repeat until both valances have all grommets installed.
  
  

Hang the Curtain Rod and Valance

• 1). Mark the screw holes of the curtain rod hardware on the wall where you want the valance. Ideally, the curtain rod will be at least a couple of inches above the top of the window. Be sure to use a level to ensure the curtain rod will be straight.
  
  
• 2). Use a stud-finder to determine if there are studs in the wall where you will be attaching the hardware. If there are not studs, it is recommended to use wall anchors to help support the curtains.
  
  
• 3). Install the curtain rod hardware by attaching it with screws at the designated locations, using anchors if necessary.
  
  
• 4). Hang the valances by threading the curtain rod through the grommets of both valance panels.
  
  
• 5). Place the curtain rod in the brackets and secure them. Most drapery brackets have a way to keep the curtain rod in place. Finally, attach the finials to the curtain rod to complete the look.