Put a tee in the ground and practice hitting that from 3 to 6 feet.
Next find a straight putt. Put the tee on the left edge of the hole. First hit the tee straight on several times. Next try to bank the ball off the inside of the tee, and into the hole, several times. You can then put the tee on the other corner and do the same. The hole will start looking very big after a while. This will teach you to narrow your focus.

I'm sure there are several variations of this drill.


For breakers... find a hole on a slope. Put a circle of balls around the hole. Make all the putts. Next make them using different speeds.

Another that I like to use as a warm up, not aiming at a hole, but use two balls - the first ball I try to stop on a 'spot' somewhere on the green at varied distances, with the second, I try to hit the first ball and stop it as close as possible to the original ball. Useful when the greens are crowded.

Not really a drill but... I like taking 3 balls and throwing them in the rough and trying to get each one up and down.