To create an efficient and repeatable putting stroke, a big key is setting up with the shaft of the putter in line with your forearms. This makes it much easier to swing the putter ... on-plane consistently and it reduces the degree to which the putter head wants to rotate open and closed. As Titleist staff member Brandon Stooksbury explains in this video, aligning the shaft with your forearms requires a grip that's significantly different than your full swing grip.