You and three of your friends can have a mini-tournament when you go out for a round of 18 holes. You write down your score for each hole on the scorecard and the player with the lowest number at the end of 18 holes wins the match. This is called medal play.
Each hole stands on its own. If you score a 4 on the first hole and and your opponent registers a 5, you win the hole and get a plus-1 on the scorecard. If your opponent scores a 5 on the next hole and you shoot a 9, he wins that hole and the match is now even. Even though you lost the second hole by more than he did on the first hole, the match is still even. The match ends when a player is ahead by more holes than there are holes left to play. So if you go to -4 after the 15th hole, you win the match because there are only three holes left and your opponent could not catch up.
One of the most enjoyable ways to compete is in a best ball tournament. In this, a foursome competes as a team. Each player will hit a drive. Then, the players use the best drive as the marker and all players hit their second shot from the spot of where the best drive ended up. The same holds true on all shots until you get to the green. The foursome that puts the best score on the board wins. This is how many company golf outings work.