A six-footer is by no means a gimme, but it's still short enough that it stings when it doesn't go in. To make more of these, start by locking in your speed. It's the most important part of every putt. And when you assess speed, don't just factor how fast the ball needs to roll to get to the front of the cup. Think about it: You're not trying to be so precise with your putting that the ball falls in on its last rotation. So forget the front of the cup. You should be looking at a spot 1½ feet beyond the hole. You'll still be in tap-in range if you miss, but now you know the ball is going to get there every time.
Once you've determined that spot, then you can read the break. Start by walking to the hole, and try to picture the line in your head, keeping in mind that it continues 18 inches past the cup. Typically a putt of this length isn't going to break that much—unless your course is Augusta National.
To get my speed down, I often practice with a small silicone cover over the top of the hole. The ball rolls right over it. If you don't have one, you can just putt over the location of an old cup like I'm doing here (see bottom photo). The point is to get the ball to stop at a consistent distance beyond the hole. After I hit a putt that rolls over the cup and stops where I want it to stop, I'll put a dime down to mark that end point. Then I'll stroke putts over the hole trying to get every one to stop on a dime, so to speak.
Having a pre-shot routine is important, but that doesn't mean only doing the same things before every putt. Just as important is the amount of time you take to do those things. It will make a big difference if there's a consistent duration from setup to stroke—it gives you good rhythm and confidence. Another thing you should do before you hit a putt is to take one last look at your line of putt all the way to the hole and then back to your ball—but do it quickly. The longer you stand over the ball, the more likely you'll start to psych yourself out that you might miss. Good putting is a lot more mental than physical. Not a lot can go wrong with your stroke on a six-footer—it's a fairly short and quiet motion. If you can relax and trust in what you've done prior to the putt, your chance of rolling one in will go way up.
If you struggle with these makable putts, it's probably because you're too focused on using perfect mechanics. I've got news for you, guys like me on the PGA Tour rarely set up and make a textbook stroke, yet the tour average for putts made from six feet last season was 70 percent. What I'm saying is, there are a lot of ways to get the ball to go in the hole.
Putting is extremely personal, but everyone should feel comfortable over the ball. I like when my arms hang freely, and I have a slight roundness to my back. As for the stroke, I don't think about the length the putter moves back and through. Instead, I try to be as athletic as possible, meaning my process is to look at what I have to do—then react. If you're shooting a basketball, you don't think about how hard your arm has to move for the ball to reach the basket, you just look at the rim and let it fly. Try putting with that same mind-set.