You have to be damn quiet, and you usually don't get very near.
Some important points that you have to note: use a long focal length. Chances are, the marshall will not allow you to get close; I do believe you have to stay behind the ropes, even if you are the official photographer. Even if you are allowed beyond the ropes onto the green, you have to stay an arms length away from the ropes.
Do not EVER shoot on the golfers' backswing, or when he is standing over the ball waiting to tee or hit. You will only succeed in startling him/her and making a bad impression for yourself. The only time you should shoot, is after the ball has been hit, on the follow through. Even if you are slightly further away, don't take the risk. You just might piss someone off.