You will need about 1/8 of a yard of fabric, two metal barrettes/ clips, and a six inch piece of soft elastic.
Step 1: Preparing the Materials
Cut fabric as follows for an adult-sized hairband
1 piece: 15 x 5.5 inches
1 piece: 10 x 2.5 inches
1 piece elastic: 6 inches
2 pieces of the barrette pattern. Then snip off about 1/4 inch from the "non-pointy" end, as shown in the picture.
Cut fabric as follows for a child-sized hairband
1 piece 15 x 5.5 inches
1 piece: 8 x 2.5 inches
1 piece elastic: 4 inches
Step 2: Sewing the Hairband
Repeat with the smaller hairband piece.
Step 3: Insert the Elastic
The easiest way to do this is with one of those little hooks they sell for the purpose of inserting elastic, but you could also use a safety pin on one end of the elastic, and pull it through with a crochet hook.
Sew both ends of the smaller tube to secure the elastic. You can sew right across the fabric, even though it's the "right side." It will be hidden in the next step.
Step 4: Sew the Hairband Together
Connect the other end the same way.
Step 5: Finish the Hair Band!
Step 6: Make the Barrette Cover
Sew the two pieces of the barrette cover together, right sides together. Sew a scant 1/4 inch seam. Turn right side out. Press flat.
Insert the metal clip. If the fit is too loose, sew a narrow top seam around the edge to improve the fit.
Fold the bit of fabric still extending past the end over the barrette, and use hot glue to secure it. Gluing a tiny bit of felt (which won't gray) over the raw edge may help make the barrette last longer.
Et voila! There you have it!