Nylon/lycra swim cap Fabric pen Sewing Scissors Needle and thread
Step 1:  Put your wig cap on your head and draw an invisible line from the inside corner of each eye up to the hem of the cap.  Mark this area with your pen.
Step 2:  Take cap off head and draw a line directly between the two previously marked lines.  This is the center of your cap.
Step 3:  Cut out two ear flaps and sew onto cap.
Step 4: Mark off areas for bangs, ears, and sides.
Have a helper tape the ear flaps on the cap while it's on your head, then exchange the tape for pins, which you can take out while you sew. You can find nylon/lycra caps at Dick's Sporting Goods, Amazon.com, and occasionally, eBay.  Wal-Mart, Target, and other chain stores do not carry them.