Good Golf Posture Will Allow You To Swing The Club On The Correct Path
You want to have an athletic setup with your golf posture and also have your weight on the balls of your feet. Having your weight too far forward or too far back in your heels may cause you to get off balance in your swing. It's also important to have good angles in your setup. If you look at the picture below, I demonstrate the proper angles that should form by bending the knees and bending at the hips. My club hangs down naturally and there is also a slight angle between my forearms and the club shaft.
It can also be helpful to look in a mirror once in awhile to check and make sure you're setting up properly. Good posture is an important setup fundamental along with proper golf alignment and golf ball position. Once you start practicing getting into good posture, you'll start to swing the golf club more easily on the proper swing path and you'll be able to hit the golf ball farther and straighter.