Putting is based a lot on your feel for distance and the speed at which you would like to roll the ball. I often think of rolling the ball out of my hand to get a feel for the distance of a putt, particularly those longer than 10 foot.

A drill I like to use for practice, as well as getting a feel for the greens at a particular course, is to stand in the middle of the practice putting green and stroke putts to stop on the edge of either side of the green.

Thereby giving you an idea of the speed and allowing you to focus on the line out on the course and not be too worried about what the speed might be.