The putting tip that will make you better guaranteed requires very little effort on your part. It may require a little rhythm, coordination and the downloading of a free app. 
I spent decades studying putting learning from the best putters, reading books from the “experts” and trying everything I could to become a better teacher and player.
There are several great putting instructors including Dave Pelz, Dave Stockton, Stan Utley and many more. Lately it appears that Dave Stockton is the “hot guy” to see for PGA Professionals, you can see a couple of his lessons located here at putting video help.
There are many areas of putting that we will not cover in this post but lets go over a few quickly before the great tip.
Grip
There is no “all in one” perfect putting grip to use. A good putting grip will give each individual the opportunity to control the putter without excessive tension. A key to keeping the putter stable is to grip the putter in the palms of both hands, this should reduce wrist action and rotation. Some great putters like a form of a standard putting grip, others double overlap, many reverse overlap and many more putt with the left hand low, right handers. The key is to get a grip that keeps the putter firmly in control in the palms of your hands and makes it easy to make a relaxed stroke without excessive wrist action. My personal opinion is putting cross handed or left hand low is probably the easiest way to not putt poorly. 
Distance Control
I am always surprised when I discuss one of the best distance control methods and a player has never heard of it? One of the easiest ways to think about and to control your distance is to take the putter back a inch for every foot you want the ball to travel. So if you have a 10 foot putt the putter should travel 10 inches away from the ball on the back swing. If its a 2o footer then use a 20 inch back swing. You may need to apply a little math for up hill and down hill putts. If you have a putt that is 15 feet and down hill, guess how many feet you need to hit the ball if it was on a flat putting surface. If it -5 fee then hit a 10 foot putt with a 10 inch back swing. Do the reverse for uphill putts.
One of the great parts about this technique is that even if the you don’t like the method it makes you think about how far each putt is. When is the last time you stood over a putt and thought to yourself, “this is about a 24 foot putt but it is a bit uphill so I better play this 31- 32 feet.” Probably not that often. So just trying this method will help you improve your distance control.
Putting stroke length
A big part of the previous distance through measurement drill is to make the putter back swing short enough as to not decelerate at impact. If you have the club head slowing down at impact that is not good, odds are your a pretty poor putter. So the drill above controls the length of your back swing ensuring that you make a impact with the putter head increasing speed.
The Big guaranteed putter tip
Studying the best players in golf takes patience and the forming of a lot of hypothesis. This one turned out to be a winner which is not always the case. When studying the best putters on tour I assumed that the time it took for the putter to leave the ball and return to impact was different depending upon the length of the putt. It is not fun to be wrong but boy was I wrong. I was so wrong I studied every tour player I could find to prove that I wasn’t wrong, it didn’t work.
All the tour players studied had the same speed from the start of the back swing to impact on all their putts. Each player had their own different time from 57 to 74 beets per minute. This was very surprising to learn that the time of the putting stroke was the same so the speed of the putter had to change. I then studied the total time from the full swing and the total time of the putting stroke and player that were fast or slow with one were the same with the other. The conclusion is good and great putters will have a total time of the stroke the same on every length putt.
Slow strokers of the ball tend to have a speed of 57 beets per minute. Fast paced players were in the low 70’s. I didn’t find anyone that was a good putter outside this range. The other oddity was the players resting heart rate also related to their natural, most effective putting speed.
So how do you find your speed?
Download a free metronome app. and go to a practice putting green. Start with the metronome set at 66 beats per second and then put the metronome in your pocket so you can still hear it. This takes a small amount of coordination but make sure you start the putter away from the ball on one beet or what ever sound the metronome makes and then hit the ball on the next beet. You may have to change the speed several times to find your perfect speed. When going through this process every player I have ever worked with found a speed that when they find it they all of a sudden they say, “wow that feels good.” With practice you will feel the pace that is the best for you. Practice at that speed with all length of putts until it becomes a habit. Remember this pace and practice keeping the same pace for all length putts.
What I found studying the pace of players on full swing and putting was that players who keep the same pace under pressure perform much better than player that don’t. Some call this choking but it really is the lack of understanding how your body works best under pressure. After practicing your putting pace you will hear the imaginary metronome sound in your head when you putt. If you do and you keep things on pace I guarantee you will put better.
Jim Hartnett, PGA
www.myhome4golf.com
