Distance control is arguably the most important component to becoming a consistently solid putter. The line you choose will be dictated by how firmly you hit the putt. (the firmer you hit the putt, the less it will break, the softer you hit it, the more it will break). Therefore if you are not in control of the speed, choosing the correct line is guess work and holing putts is even less likely!
A common issue I see which makes distance control difficult for amateurs is a poor grip and excessive wrist hinge. Gripping the club too much in the fingers encourages more wrist movement and enables the player to easily hinge their wrists during the stroke. Hinging and unhinging can add excessive speed at the bottom of the arc and make it more difficult to keep the club face on line.
Ensuring the club is positioned in the palms of both of your hands (a larger putter grip can help with this) and trying to maintain the Y shape created between your forearms and the putter throughout is a great start to making your putting stroke more technically solid. It will encourage you to use your larger muscles to control the putter making distance and club face control far easier.
Taking your focus away from the hole is a great way to focus your mind on making a good stroke.
After selecting the line of your putt, pick something small a few inches in front of the golf ball on your intended line. Have a couple of practise swings to give you the feel of how hard to hit the putt then focus on stroking the ball over your chosen spot.
Selecting this intermediate target will also tell you what elements of your putting you are doing well and what perhaps needs more work Ie if you always hit the ball over your intended line but you aren’t holing the putt, either you are hitting the ball too firmly or softly for you intended line or you are not reading the green correctly but if you aren’t hitting your chosen spot regularly, its perhaps a mechanical issue with your putting stroke.
The putter is going to be the most used club in your bag during a round of golf (unless you are having a truly terrible day from the tee!). Improving your putting by even a very small percentage will often reflected in your scores almost instantly however it never ceases to amaze me not only how many putting lessons I give in comparison to long game lessons but also how few players have their putters fitted to them.
There are hundreds of shapes of putters with varying weights, shapes, lengths etc, spending a bit of time to learn more about your putting stroke and getting fitted for a putter is money well spent if you’re serious about trying to lower your scores!