Getting the position of the trail hand in putting just right is THE fastest way to improve.
What I want you to do, starting from the next time you even touch a putter is to put the lifeline of your trail hand on the side of the grip, directly behind the shaft of the putter as it strikes the ball like this:
In these images the black line is showing where my lifeline is and you can see in the right-hand picture - from the player's point of view - that this goes on the right hand side of the grip. Remember - it would all be reversed if you're left handed.
The force of your arm is applied through the lifeline area of your hand. You want this force to be delivered directly behind the putter, so that it pushes the putter head towards the target, rather than anywhere else!
Because all the force is directly behind the putter shaft, the putter twists much less if you miss the putter's sweet spot (which we all do some of the time).
Having your hands in this position reduces wrist action, which leads to inconsistency (and in extreme circumstances the YIPS).
I can remember as clear as yesterday the first time I got this right. The roll I put on the ball was so much better and the start line so much more consistent than before. My putting changed overnight because the trail hand in putting is one of the absolute keys.
If you need any convincing, look at these two pictures of decades-long top pro putters Phil Mickelson and Steve Stricker:
Notice how little of their trail arm you can see from this behind-the-hole view?
That's because they have the trail hand gripping the putter with the lifeline on the side of the grip. They deliver the putter with all the force behind the shaft and that's one fundamental reason why they're great putters.
Here's the best drill for you to get into this position:
When you next pick up a putter hold it with your thumb at the top of the grip with your lead hand (left for right handers, right for lefties) and then lay the putter grip directly up the lifeline of your trail hand.
If you do this right, the grip should appear to run up the inside of your forearm, as you can see in the right pic.
You will have to get used to the rest of your fingers being a different position , as they won't be able to wrap round the grip, but TRUST ME... It'll be worth it!
Look forward to sharing another ABSOLUTE MUST for great putting with you tomorrow.
Until then... roll 'em straight and true!