While it is the usually the slowest part of your swing, the backswing is integral to making a good shot in that it sets up everything that follows in the downswing, the strike of the ball and the follow-through. If you are out of alignment or off plane during your backswing, you are unlikely to make a shot and will certainly struggle throughout your round.
One Piece Takeaway
It is vitally important to your golf swing that all your body parts work together toward your goal: your target. To that end, your backswing should begin with all pieces moving in concert. Your hands, arms and shoulders should form a triangle, and as that triangle begins to rotate away from the ball, your hips, legs and feet should move together, making a single, powerful engine ready to launch the ball toward your target.
Straight Front Arm
Keeping your left arm -- or right if you are a left-handed player -- straight is one of the first thoughts your first instructor drills into you. But why? Keeping your forward arm straight throughout the stroke anchors your arc to a consistent length throughout your swing, enabling you to return the clubhead to the same spot at the back of the ball where your swing began. This makes it far easier to hit the ball crisply on the down stroke.
Brush the Turf
Keep your clubhead low and straight along the ground as you take your club back smoothly. Smooth is the word--a low, smooth takeaway promotes a long, smooth arc back into the ball on the downswing, which translates into power.
Shoulder to Chin
Where is the top of your backswing? Some players take their clubs past parallel while some never reach more than a three-quarters swing. The common element among good players is that their left shoulder (right for left-handers) reaches and virtually touches their chin at the top of their swings. This is a great position and virtually guarantees your swing is completely loaded before pulling the trigger.
Another important part of your swing is the transition: the spot where your backswing changes direction and becomes your downswing. Keeping a smooth tempo in this transition makes the difference between keeping your club face on line and maybe missing the ball entirely. Stay smooth and hit the ball solidly.