Straight back and straight through putting is very effective when putting inside fifteen feet and requires that you keep the putter face square to the target line throughout the entire stroke
Practice getting a great swing plane by placing your golf bag on the ground behind you and matching the angle of the bag with your backswing and follow through
Working on your swing in slow motion will allow you to analyze what you are doing on each part of the swing, which will help you fix your flaws but also get away from swinging segmentally