Step 1: Acquire scrap leather
Fake fur makes an especially tasteful accent; be creative.
Step 2: Make a bikini: pattern
Trace the pattern onto the leather, making sure you mark the orientation properly. Add fake fur to the top, as this will (partially) help cover up the fact you've used a crappy pattern.
Step 3: Measure twice, cut and sew
Trace and cut out a pattern, double-check it, then actually cut your leather and sew the thing together.
Check again, just to make sure, as this is the most squirrelly piece to fit.