Straight Left Arm
If you are having trouble with your golf swing, chances are you were told to keep your left arm straight.
WRONG: You see when you keep your left arm straight you anatomically cause your left wrist to bend back which causes the clubface to shut. All of this stalls the engine room or rotation in your swing causing it to get too steep.
So if this is you a good drill to do is: As you start your swing bend your left elbow pointing it out towards the ball, this will narrow your radius and allow the club to swing in its proper arc.
Beware: If you slide too much or sway this will not work.