This is the key to eliminating the dreaded three putt.
Holing putts is almost entirely dependant on how far you are from the hole. You are twice as likely to hole out from three feet than you are from six and half feet so getting the ball as close to the hole as possible is the main priority with your first putt.
With very little technique in mind, simply throw a handful of balls down on the edge of your clubs practice green, roll one ball to each flag and keep score of how many finish within three feet of the hole.
Every one that doesn’t is a potential three-putt so keep practising this with the goal of improving on your previous score.