When it comes to putting, there are two schools of thought:
1) Let the putter head rotate and swing on an arc.
Or,
2) Keep the face square and make the path of the putter stay on the target line.
If you fall into the second camp of thinking, Titleist Staff Member Michael Breed has a great drill for grooving the feeling of a “square-to-square” stroke with the aid of a gear tie, an inexpensive gadget that you can find at your local home improvement center.