Many golfers can not get into a proper set up position and posture because their hamstrings are too tight to allow the straightening of the back, so before you tee off or practice work on stretching out your hamstrings so that you can work the golf swing properly around a straight back
Tightness in your calves, hamstrings and buttocks can hurt your golf game by leading to a straight and upright posture
PGA Pros know the exact distance that they hit each club and you should as well, go out to the range when it is soft and hit each club in your bag squarly and mark each distance so you never select the wrong club again