Rhythm is the key to a better roll
To get the ball rolling and hugging the green on long approach putts, think in terms of making a longer, flowing stroke -just as you would if you were asked to bowl a ball across the green.
'Measure' your stroke
Generating momentum with your swing is as important in putting as it is in the long game. The further you are away from the hole, the more important it is that you stand up a little taller to the ball, and think in terms of creating a longer flowing stroke that really gets the putter-head swinging - thus enabling you to get the ball truly rolling across the green.
What you must never do is rely on a standard length stroke and expect to adjust the amount of acceleration through the ball to find your distance. Long-term, there is simply no consistency in that at all. Good players lengthen and measure their putting stroke to suit the length of the putt they face - and that's exactly what you must do.
Think about the way a bowler would roll a ball across the green - the further he has to roll the ball, the longer the arm-swing and the greater the momentum there is to generate the necessary pace.
The same rules apply for the golfer with a putter in his hand. With a relaxed grip pressure, you want to get a sense of swinging the weight of the putter-head.
As you then flow the putter back and forth, you will be aware of a certain 'lag' in your wrists as your hands respond naturally to the motion. Eliminate any tendency to be 'wooden' and instead get some rhythm and fluidity going.
With practise you will quickly begin to strike the ball more solidly and you will enjoy lagging your approach putts to the hole with a noticeably pure roll.
When you practise, stick a few tees in the green to give yourself some random targets to aim at, and work between them to fine-tune your sense of distance control.
By far the majority of three-putts are the result of either coming up short or knocking the ball way past the hole.
The quicker you get to work on improving this aspect of your game, the quicker you will start saving shots.