Hitting the ball with the sweet spot of the putter allows the putter face to stay square and not twist
There are two ways to practice the short game. First are how-to shots, where you learn how to control trajectory through set up and swing shape. Second are situational shots, where you move around the short game area and practice specific shots.
Catching he heel of the club, near the hozzle, results from an inside out swing where the clubface at impact has moved away from your original set up position