Here are a few putting green etiquette guidelines provided by the USGA.
1. Avoid walking on another player’s line of putt or casting a shadow on that line, and the area extending beyond the hole, while the player is making a stroke.
2. Do not cause a distraction by standing too close to the ball or hole.
3. The first player to hole out should position himself/herself to replace the flag stick once play of the hole is completed.
4. All players should remain on or close to the putting green until every player has holed out.