Etiquette on the golf course is essential no matter where you play.  However, an exclusive invitation to play a private course, either in a small group or tournament, comes with certain expectations.

First, relax! If the invitation was from a business associate, it is to build your business relationship in a casual manner. If your friend extended the offer then it should be a relaxing and fun day with opportunities to meet some other great people.

Private golf clubs seem exclusive and tough to get into, but you can follow several easy tips to ensure a successful day on the green.

Preparation
•    RSVP promptly
•    Depending on how well you know the host, brush up on their information. Where did you meet? What do you know about their personal life? Do a little research and determine what common interests you have in order to start a good conversation.
•    Clear your calendar for the date of the tournament. Be sure to write down the tee time.
•    Find out what the proper dress code is. Some clubs may have different dress codes and you do not want to show up unprepared. Also, check the dress code at the on-site restaurant because you will likely be dining there after the round of golf.
•    Pull out your best golf outfit.
•    No matter what your golf game level is, it is helpful to take a lesson and show up in your best shape.
•    Get out your equipment. Clean your bag, buy new balls and a new glove to look the part and play the part.
•    Call the club and ask if it is okay to walk the course ahead of time. Your host knows the course well and it will help if you familiarize yourself with the yardage, doglegs, and hills ahead of time.
•    Brush up on golf etiquette in general to reduce the risk of embarrassing yourself. This will help you have the demeanor of a professional, even if you are secretly a rookie.

Now that you have fully prepared for a day out on the green, it is time to review etiquette for the big day.  Most importantly, relax! All of these tips, etiquette, and advice are to help you have a great day of golf.

Day-of Etiquette: Before you start
•    Private v. Public courses: A private club is more conservative about course rules, dress code, and etiquette. Find out the specifics beforehand.
•    Do not be intimidated by the other golfers, they are not necessarily better than you. Just play your best game and have fun doing so.
•    Know the course rules ahead of time. The rules will be posted in several locations; glance over them a few times to prevent any confusion.
•    Depending on who is inviting you, it may be courteous to offer to pay the greens fee. If this is a business relationship outing, there is a good chance it will be paid for. If it is a group of friends, the fee per person should be stated up front.
•    VERY IMPORTANT: Be on time for your tee time. You should arrive 30 minutes to one hour early to be sure you have your equipment together and warm up. If your tee time is at 9:23, you will be teeing off at exactly that time. 
•    Arrive with cash to tip appropriately. Check the tipping policies beforehand, but you will likely need to tip your caddy, beverage cart attendant, valet, bag drop attendant, etc.
•    Be prepared to gamble. You may choose not to gamble and if you do gamble, you may not lose, but it is better to have cash in different denominations in order to pay up quickly if necessary.

In-game Etiquette
•    Do not make any unnecessary sounds such as jingling change in your pocket or whistling while someone is taking their shot. These types of distractions are very rude and will probably ruin any chance of future golf outings.
•    Be ready when it is your turn. In order to keep a steady pace on the course, everyone needs to pay attention to when it is their turn. This is very important in helping prevent any wait time for the group behind you.
•    Maintain the course: fix divots, rake the bunkers, fix ball marks on the green, etc. Private club members have pride in their club and you should show them that you care as well.
•    Depending on the relationship, it may be polite to offer to buy lunch.
•    Cocktails will probably be served, but be sure to limit yourself and remain respectful at all times.