Measure the diameter of your curtain rod or metal cording and add ½ inch or more to determine the size of grommets you need. Purchase the appropriate size grommets and the correct amount. A pair of curtains may use 20 to 30 grommets, depending on the width of the window.
Spread out the drape material on a flat surface, the front of the fabric facing up. Place a grommet every 8 inches across the top of the fabric, starting and stopping at the corners. Position each grommet at least 1 inch down from the top edge. Trace the inside edge of the grommets onto the fabric and set the grommets aside.
Sew a circle just outside of the drawn circle, using a zigzag stitch. Cut away the inside of the circle if you’re going to use a sewing machine. If not, cut out the fabric along the drawn line and apply anti-fray liquid to the cut edges. Allow the liquid to dry.
Separate each grommet into front and back halves. Hold the back half of the grommet behind the drape and slip its center prongs or lip into the cut circle. Set the material and grommet on a flat surface with the grommet half against the surface.
Align the front half of the grommet with the circle to sandwich the drape material between the two halves. Push the front half downward into the back half until it clicks into place with a snap. Lay a cloth on the grommet and tap into place with a hammer, if necessary, to force the two halves to connect.