Don't use your full-swing grip when putting
The instructor stresses not using your normal full-swing grip when putting, because that grip is designed to get the wrists hinging and creating speed, which you don't want on putts. Putting is about controlling the face angle, so he uses a reverse overlap grip: all the fingers of the right hand on the grip with the left finger overlapping. Choosing a putting-specific grip helps quiet the wrists and control the face.
Channel: Dan Grieve
Watch official source at 6:39