Equipment Needed
Step-by-Step Instructions
Get a thin piece of string about 10 feet long and two alignment sticks (or nails/tees to tie the string to). Choose a straight, flat putt on the practice green of around 8-10 feet.
Secure the string about an inch above the ground, running from just behind the hole back along the intended start line of the putt. The string should be taut and directly over the line on which you want the ball to roll. One end can be tied to a stick stuck in the ground behind the hole, and the other end to a stick near your ball (use tees if sticks aren't available).
Place a ball under the string at the starting point. When you look down, you should see the string appearing to bisect the ball and lead straight into the center of the cup. This is your perfect line.
Make your stroke, trying to roll the ball directly under the string's path. The feedback is immediate: if the ball rolls along the string, you've started it on line. If it veers off, your face or path was off.
Putt repeatedly along the string. This will train your body to align properly and your stroke to deliver on the intended line. Once you remove the string, the visual of that straight path often remains, and you'll have confidence hitting straight putts on your chosen line.
Professional Endorsement
Using a chalk line or string for straight putts is a common tour practice routine. Tiger Woods is frequently seen practicing with a chalk line on the green to ensure he's rolling the ball on his intended line. Many pros, like Dustin Johnson and Rory McIlroy, use alignment strings in their putting drills to keep their stroke honest.