Try letting the left hand control the entire putt. From the takeaway to the stroke. This should give you a smooth takeaway and finish. You maybe gripping the club too tightly with the right hand and letting the right hand also control the swing. If you grip the club too tightly with the right hand (assuming you are right handed) there is a tendency to rotate the face closed. Try gripping the club with just your right hand and squeezing hard on the grip. You should see the club rotate left. Hope this helps.