Keep Up the Course
While it may be up to the greens-keeper and his staff to present the golf course in excellent condition, it's the caddy's responsibility to keep it that way for golfers to enjoy. That means the caddy should replace all divots that he sees, including those made by other players. In addition, he should rake the sand traps after his player has hit a shot so that they will be playable for those who are in the trap later. Once on a green, a caddy should repair all ball marks whether they have been made by his player or not. The standing rule that caddies should follow is that the course should be in better condition as a result of his efforts.
Know the USGA Rules
It is the caddy's job to make sure that his player is following the rules of golf. For example, you should know that a player is limited to 14 clubs, and it is your job to count the clubs in his bag before the round is started to make sure he complies. a caddy should know what constitutes a ball that is out of bounds, and the different penalties that are assessed based on the type of hazard his player is in. The rules of golf are voluminous, so it is imperative for a caddy to have a rule book with him at all times.
Carry the Necessities
Put together the items necessary to do your job as a caddy. Besides having a rule book, you should carry a clean, large towel that you will use to keep your player's clubs spotless during the round. Before your tee time, wet half of the towel to do the job. Carry a supply of adhesive bandages in case your player develops a blister. Also, have an extra pencil and a scorecard of the course in the event your player forgot to bring one. Finally, carry a repair tool to fix ball marks left by preceding players because, as said earlier, it will be your job to keep the golf course in great condition for the players behind you.