1. Cut strips of the fashion fabric and waistband interlining to make a waistband. They should both be 10cm (4") wide and your waist measurement plus 10cm (4") in length.
2. Sew them together, wrong sides together.
3. Press in 1.5cm (5/8") along one long edge.
4. Place the other long edge of the waistband centrally along the pleating, right sides together, with an equal amount of excess hanging loose at each end. Sew it down.
5. Turn in the ends of the waistband in line with the edges of the skirt opening and press, then sew them down along the stitching line.
6. Baste the short edges of the waistband to the interlining, ensuring that the stitches don't show on the outside.
7. Cut two 15cm (6") lengths of 15mm (0.5") wide ribbon, fold them in half and pin to the waist seam on the inside. They will help you hang the skirt up when it's finished.
8. Turn the pressed edge over to meet the pleats on the inside, covering up the ribbon ends. Stitch down strongly by hand, or alternatively by machine as follows:
9. Pin and baste the waistband edge down, hiding the stitching line. Turn over and stitch from the right side ensuring that your stitches fall in the "ditch" between the pleats and waistband edge.
10. Insert your drawstring. Secure a safety pin in one end and pass the safety pin all the way through the waistband.
11. You may want to add a "modesty" panel in the skirt opening - simply sew a 20cm(8")x10cm(4") rectangle of fashion fabric to lining, wrong sides together, press, turn out and handsew the opening closed. Then sew one of the long edges to one side of the opening with the top edge in line with the bottom of the waistband and a little excess hanging below the level of the bottom of the opening on the inside.