It is a tricky shot to learn, however the best way is to experiment and hit a thousand on a the practice green.
It does help to have a wedge that has a thin sole with a compact grind on the head, I have Mizuno MP-r's and they set up perfect.
The tour pitch is also a shot you play off of tight lies like fairways on tour.
The main idea behind the shot is the angle of attack.
You want to almost skull the ball , but with the face of the wedge not the sole.
You slide the leading edge right underneath the ball and let the ball slide up every groove on the face to get all that spin
you don't want to hit down on the ball really at all, which is of course why the pros make no divot when they hit this shot
your angle of attack is basically straight into the ball and straight through, pretty close to 0-degrees for all the Trackman users out there
A great way to practice this shot is to find a tight lie and make some swings with no ball just moving the grass blades, your not taking a divot and your not even cutting the grass, just moving it.
Then practice some shots off of hardpan, because if you hit down on the ball then with the leading edge in front, the club will bounce off the ground and you might kill someone in the parking lot
Think of the shot as if you are hitting off of a cartpath and your using a new wedge, you want to make could contact with the whole ball, but you want to put the smallest scratch possible on the bottom of your wedge.
Good luck and keep practicing