Start with a landing zone
Find a quiet part of the practice green. Put a tee a comfortable distance away and imagine a small circle around it. Roll five balls towards that zone without worrying about a hole. Notice how far each one travels.
Build a ladder
Set three tees at roughly three, six and nine paces. Roll one ball to each, working up the ladder and back down. Let the size of the stroke change naturally while keeping your movement smooth. Avoid trying to force the ball with a sudden hit.
Use your eyes and your feel
Before each putt, look at the distance and make a practice stroke while looking at the target. Then roll the ball and compare the result with what you expected. The feedback matters more than repeating a perfect-looking stroke.
Bring it to the course
Give yourself a few minutes on the practice green before a round. Test short and long putts, especially if the surface is wet or unfamiliar. On long putts, focus on finishing inside a comfortable second-putt distance.