Keep a firm grip on both pinches and uncross your hands while simultaneously lifting the shirt off the surface. You 'must move your left hand through the two folds of shirt hanging from your right hand during this uncrossing motion. If you uncross your arms simply by rotating the shirt instead, you will end up with a mess.
This is the easiest part of the fold to mess up. However, once you've understood the type of motion you need to make, it will be easy and quick.