One major fault I see in most members golf swings is the poor transition from the top of there swing to the start of there down swing. One of the hottest players and best ball strikers on tour at the moment is Hideki Matsuyama who has a distinct pause at the top of his golf swing. What this does is it allows the body to fully wind up and coil to a stopping point which in turn allows you to start your downswing with everything working together and in sync which I believe is the most important moment in the golf swing. If your quick from the top of your swing you will lose all connection between your rotation, arms, big muscles and golf club commonly creating an over the top slice action.
Tom Ballard