Step 1:
Using two tees, setup a gate a bit wider than your putter, relatively square to your intended target line.
Step 2:
After making a few test putts to find where the breaking point is on the green, setup a second gate at that line. If you can roll the ball to the breaking point, your second putt will be effortless.
Step 3:
Practice putting the ball from the first gate to the second gate and letting the landscape do most of the work for you. By aiming toward the second gate rather than by aiming directly toward the hole, you will have a much better chance of making that second putt.