With very few exceptions, the backswing is the most important part of the total swing. Without a backswing that puts you in a position to deliver the clubhead back to the ball in a square position at impact, your ball striking will be very inconsistent at best.
There are five key essentials that must take place before starting the clubhead away from the ball: ball position, stance, grip, posture and balance.
I feel the grip and balance are the most important.
The proper grip will help you keep the clubface in a good position throughout your swing and balance will help maintain your posture, commonly referred to as spine angle.
The golf swing starts from the ground up. The clubhead starts moving away from the ball with the left arm and left shoulder following to extension. The left shoulder moves behind the ball to a coiled position with your weight on the inside of your right foot and leg with very little hip movement.
During this extended move away from the ball, the shaft stays between your arms and will be parallel to your target line at the top of your backswing.
Practice this move away from the ball with a mirror behind you on your line until it feels comfortable.