There is a large body of teaching professionals that believe that the most important fundamental in the golf swing is to "sustain your line of compression". This is a fancy phrase but what it means is that you want to keep the ball in a compressed state, meaning part of the ball is flattened on the club face, as long as you can through the impact zone. This leads to very solid contact and ultimately more control with all  your shotmaking. 

This video shows one of my favorite drills to give you the feel of keeping the club head low after impact so you can compress the ball consistently. Please watch for a full demonstration.