This story is for you if...
1. Your most common missed putt is a pull.
2. You're way off on left-to-right breaking putts.
3. You hold your putter as tightly as your driver.
Everybody naturally favors their dominant hand, so most right-handed players grip the club tighter with their right hand than their left. This uneven grip pressure causes you to flip the putterhead past your hands through impact and pull the putt left.
Check your grip pressure. Your hands should feel very light on the handle, much lighter than with a full swing.
HOW TO CHECK IF YOUR GRIP IS TOO TIGHT
Wrap some aluminum foil around the grip of your putter, and then roll some Play-Doh or Silly Putty over the foil, creating an impression pad for your grip. Roll a few putts on the practice green, then check the indentations made on the handle during your strokes. If you see deep imprints, your grip is too tight, and you're probably flipping the putterhead past your hands. Lighten your grip until you can make your stroke without making deep imprints on the handle with either hand.