It is absolutely vital that you consciously make a full rotational movement of the shoulders during the back swing movement thus moving the arms to the end of the back swing movement.
So remember this statement:-
If you are experiencing erratic golf shots, it is most probably
because you have fallen in to a habit of lifting the arms/golf
club to the end of the back swing movement - instead of making a full rotation of the shoulders to move the arms to the
end of the back swing movement.
Therefore in order to play good golf, you must
hold the elbows close together, keep the biceps against the chest
cavity thus forming the shoulders and the arms into a very compact
unit, keep the arms in a totally passive condition -- and literally
use the rotational movement of the shoulders to move the passive
arms/golf club to the end of the back swing movement.
(To a casual observer, a back swing movement as performed by a golfer who
lifts the arms during the back swing movement will appear
to be same as a golfer who uses the shoulders to move the arms,
simply because the shoulders automatically follow the movement
of the arms, however their is a big difference between the two methods.)
Therefore from the moment you begin the golf swing you must
make a conscious effort to ensure that the upper body unit remains
firmly held together and use the rotational movement of the shoulders
to move the passive arms to the end of the back swing movement.