I am of the school of thought that all putting woes are the result of poorly fitted putter lengthwise and lie wise. You must be able to:

1) bend over enough to allow the putter shaft and you spine to be 90 degree to one another and have the ball directly under the eyes, if you can only do one or the other, the putter is NOT fitted to you correctly, and from that point on you will always be attempting to make adjustments in the stroke, hard to do consistantly. Once you have a correctly fitted putter, to place the hands correctly (grip it) you must find your natural grip, start by gripping left hand only in the correct posture as stated above with the eyes over the ball, now close your eyes and swing the putter back and forth several time (this keeps you from making adjustments visually, now return to center open the eyes, is the face still square, open, closed, make grip adjustment and repeat until you can do it and have the face square consistantly. Do the same for right hands to determine it's hand position, then with both hands.

After you achive all these, posture, eyes over ball, fitted putter and correct grip for you, you will have a consistant stroke, then the long task of learning to read putts will be the only obstacle...lol..good luck.