all i can say is that if you miss it left or right consitstantly your either pulling it or pushing it. And to fix that check to see if your putter face is open or close. another thing is if you miss it high or low consistently then you aren't reading it right on every breaking putt there is something know as an apex, or center of the arc line for a breaking putt) you must aim just above the apex to make a putt at the right speed
sorry if you don't understand it is hard to explain


another thing could just be your confidence