A while back, my mother in law gave me this beautiful blue and white tablecloth. She had paid a pretty penny for it, but it had gotten a tear in the middle and was beyond repair. She asked me to transform it for her and make it usable again. After much probing, she admitted that she wanted napkins.
While placing the napkin wrong side up on my ironing board, I pressed two opposite edges down (folding once, then folding again, concealing all raw edges). I then sewed these two sides.
After the two sides were sewn, I clipped the corners at an angle to eliminate bulk when folding.
I did this same thing last fall for my friend Tonya. She posted about it here on her blog.