50% of all putts are from inside 6 feet so the fastest way to lower your handicap and/or score is to make more putts inside 6 feet. PGA Tour players average 28 putts per round and make 65% from 6 feet. If a tour player makes 95% from inside 6 feet, they will shave 4 strokes which usually is the difference between winning and losing a golf tournament.
One of the best drills I use with my golfers is to set up 6 golf balls 1 foot apart beginning 1 foot from the hole. That will give you a 1, 2, 3, 4, 5 and 6 foot putt. Beginning with the 1 foot putt, putt all 6 golf balls in less than 15 seconds. Most will make 4 out of the 6. Then ask yourself, what did you think about as you were putting? I typically get, "I don't know." Which is exactly the point, you were thinking about the path, hole, speed or your putt stroke. My dad had a saying, "paralysis by analysis."
Next, I want you to set up those same 6 golf balls 1 foot apart beginning 1 foot from the hole again. This time when you putt, I want you to look at the hole just before you make your putt stroke. While still looking at the hole, putt the ball in to the hole. Putt each ball using this routine. Remember, the clock is ticking. Putt all 6 golf balls in to the hole in less than 15 seconds. Most will make 6 out of 6. Now, ask yourself that same question. What were you thinking about? The most common answer I hear is the "hole". The point of the drill is to make you more target oriented.
Whether or not you choose to begin looking at the hole when you play is entirely up to you but for purposes of this drill and during practice sessions, I urge everyone to try this drill. After the fifth time you try this drill, I guarantee you will become confident inside 6 feet and make more putts from inside 6 feet.