Good left arm and wrist positions at the top of the golf swing can give you more accurate, consistent drives.
Here is a great tip from the guys at Me and My Golf on how to get straighter drives by getting your wrist angle correct at the top of the swing.
This can be a difficult golf tip to explain without making it too complicated. But these guys do a great job of explaining it clearly and a finishing with a nice drill to get you in the right position. Well worth a watch.