I get on the practice green and place a tee in the ground every three feet (or putter length) starting from the edge of the fringe. I do this all the way back to 51 feet (17 tees). I only use one ball during this drill because I putt from each tee towards the fringe and try to get every putt to barely roll onto the fringe and stay there. I don’t putt at a hole on the green because I am more concerned about distance control than I am line, once I get out to 20 plus feet.
Why three foot increments you ask? Because I also have a three foot drill I use with my students from four different angles of straight uphill, straight downhill, right to left and left to right. Make 25 in a row from each spot and move onto the next one. The goal is to make 100 three foot putts in a row, if you miss #99… start over. I use both of these drills with my students because (1) you’re lag putting will improve. (2) a good lag putt isn’t a good lag putt if you can’t make the three footer. The goal of lag putting is to LAG your putt up to the hole not make it, so you lag something to three feet so you can knock in that three footer.