And, that stands for Folding Fitted sheets!
Here's a YouTube video I found and this guy uses a technique that is nearly identical to mine:
It's only a couple of minutes long. Watch it and learn. It's SO easy!
I've found it's easier to do on larger sheets (IOW, crib sheets are difficult), but just employ the main technique of gathering those corners together, smoothing as you go, making it all a perfect rectangle and you'll be folding beautiful fitted sheets before you know it!