The bottom of the clubhead should lie flat on the ground, if it lies on the heel the ball goes left and on the toe it goes right, which in turn will cause you to manipulate your swing, but the ball moves right and left depending on the club you are using so every club needs different amounts of manipulation
Gripping the club too tightly is a fatal flaw in the golf swing, it creates tension in your arms and tightens your muscles and the one thing we know is that tense muscles do not work very fast, causing swing faults and destroying your distance
Play more break than you think necessary, playing too little break makes for longer second putts because every rotation of the ball past the hole is moving away from the hole and makes your next putt longer