Golf is a very genteel game. Far more so than any other game, in golf, your manners matter. This is in part due to the lack of any referee or judge and partly due to the slow pace of the game; in any event, you are expected to know not only the letter of the law (the rules) but the spirit as well.

Another reason manners are so critical in golf is because in golf so much is dependent upon the other players. Your pace of play and even your personal safety depend upon the actions of the other players. In this sense, the etiquette of the course is actually part of the game. In the manners you show on and off the course, you demonstrate your love for the game and your respect for its traditions. 

Do:

• Do remember that pace of play is important. Everyone enjoys a nice game, but no one wants it to take all day and into the night. With this in mind, try to stay with the group ahead of you. If there is a serious gap developing, let the group behind "play through", or go past you.
• Do watch out for other's safety. If it looks like your ball could hit a group or another player, yell out "fore" to give them a warning.
• Do pay attention to the warnings and safety suggestions on the golf cart. No one wants to have their game interrupted by a trip to the emergency room.
• Do try to stay off the grass with your golf cart as much as possible. Some courses will post signs that ask you to stay on the cart path, while others expect you to just use common sense. If you are unsure, ask, and then do what they tell you.
• Do follow the "90 degree rule" if it is in force. The 90 degree rule says that you drive on the cart path until you reach a place 90 degrees  (even with, in other words) from your ball, then you turn and drive up to your ball. After hitting the ball, you turn around and drive back to the path by the same route. This will minimize the amount of damage to the turf while still letting you get to your ball.
• Do watch your shadow! It is considered quite rude to let your shadow fall across another player when he is playing or fall across his putting line.
• Do plan ahead. When you leave the cart to go play, consider taking a few clubs with you. Nothing is worse than being with a player who has to make 3 trips back to the cart to change clubs.
• Do be prepared to play when it is your turn. Nobody likes having to wait, so try to keep up.
• Do plan your shot before it is your turn. Don't wait until it is your turn to decide what clubs to use, the hazards involved and so on.
• Do be quiet. Golf requires concentration and focus to do well, both of which are hard to pull off if the player behind you is yelling "Yeah, Baby!" over and over.
• Do keep your cart off the green and away from the hazards. This game is tough enough without you introducing new obstructions and the greens are very sensitive.
• Do repair any divots or ball marks on the green, even if another group left them. Think of the people behind you. Some courses would rather you not replace the divots but instead give you a mixture of sand and soil in a bucket on your cart to fill in the holes. The first time you play a course, ask which method is used.
• Do rake out the sand traps after you hit the ball out to erase your footprints and any damage you did.
• Do leave the rake outside of the bunker after raking, with the handle pointed toward the tee.
• Do encourage "Ready Play" if you are not in an actual tournament or other "official" event. In strict rules, the player whose ball is furthest away from the players is the one who hits first but in Ready Play, this rule is ignored and the player who is ready goes first. Of course, you have to have the permission of all the other players in your group.
• Do make sure that everyone knows that you are playing Ready Play. If they do not, it is easy to hit someone with your swing by mistake. If you are playing Ready Play, announce it before you hit the ball so everyone knows who is swinging and when.
• Do watch the shots of others playing with you. Often the sun will get in the eyes of the person hitting the ball and they will lose track of the ball. If you saw where it went, they will appreciate the help and it will move the game faster.
• Do wear soft spikes and not older ones made of metal on your shoes. It is better for the greens.
• Do be aware of the location of everyone's ball when you get to the green.The main reason for this is so you do not step in someone's putting path.
• Do offer to tend the flag stick for other players in your group. This is a reciprocal courtesy that they will (or should) offer back to you when the time comes. But if you do tend the stick for another player, become invisible. This is not the time to smack your gum, dance around or scratch.

Don't:

• Don't hang out. If you are finished with putting, then get off the putting green and let the next player play.
• Don't run. Running is noisy, distracting and rude. Walk quickly if you must, but never run.
• Don't start swinging your club until you know that all the other players are a safe distance away. Be aware of your surroundings. By the same token, keep your distance when the other players are swinging.
• Don't take more than one practice swing per shot. If you add just 30 to 45  seconds to each shot, you could add an hour or more to the length of the game.
• Don't aim your practice swings at others. If you are doing practice swings, make sure other players are not in the direction you are swinging. You never know when your swing could hit a pebble or twig that could hit another player.
• Don't spend too much time looking for lost balls. Yes, the rules say you have five minutes, but if you plan on taking the entire five, let the folks behind you play through.
• Don't make divots with your practice swing.
• Don't scream or yell after taking a shot. Even if it does not bother your partners (that is a big if, let me tell you), there are still other players who may be within the sound of your (very loud) voice.
• Don't walk through a putting line. Greens are sensitive and your footprints could change the path the ball takes. Try to always walk around or behind, never across.
• Don't throw your clubs. Just don't. It is childish, immature, rude and dangerous to other players.
• Don't be rude if you need to play through. Asking to play through always carries the implication that the group you want to pass is moving slow and they are being rude.  Generally, it is better for them to make the suggestion that you can play through, but if you do ask, please do so in a nice, respectful manner and at a convenient time in their play.
• Don't play through and then be a green hog. If they let you play though, don't take 5 practice swings on each shot or 3 Mulligan's on each hole.
• Don't enter a bunker from the high side. It can cause the walls to cave in and they are very difficult for the groundskeepers to repair.

Etiquette in golf is a lot like shaving or bathing. No one is going to give you any credit for doing it, it is just expected. However, if you don't do it, you are a bum.

If you are ever unsure of  what golf etiquette calls for in a given situation, always err on on the side of courtesy. The rules and ettiquete are in place to ensure that all players get the maximum enjoyment and pleasure from the game.