Remember that an umpire is an unfortunate necessity, and his first object should be to make himself as little conspicuous as possible, and to annoy the players as little as he can. What the players want is an umpire who will attend to the game and will give an honest decision as quickly and distinctly as possible. They do not want any fancy umpiring done at their expense.
About the worst umpire that there can be is one who is trying to show off his umpiring. I believe myself that players are as a class the best umpires. They are more used to watching the ball, and will, therefore, see it more correctly. Besides, they understand better what the players look for in an umpire.
It is your duty to keep the net at the right height, and you should arrange it before play begins, and from time to time afterwards, but don’t get down to look at it in the middle of a game, unless it is absolutely necessary. Look to see that the inside posts are in place, if any are needed, and that they are not there for a double game.
Enforce the rules strictly. It is not for you to discuss them during a match, but simply to take them as they stand. The moment that you relax them you have no guide left. Be careful to find out beforehand how many sets are to be played, and if they are vantage sets or not. In case of any question arising about the rules, send at once for the referee.
No matter at what height you stand, it is impossible to see the farther side-line properly; and the same is true in a smaller degree of the base-lines. It is nearly impossible to call foot faults and to watch the service-line too. You, therefore, need at least three line umpires. If you cannot get men whom you can trust, it is better to umpire the base-lines yourself. It is a mistake to let a man take the side-line and one of the base-lines too. He will have to stand away from both lines, and in such a place he cannot see the base-line as well as you can yourself, and he cannot umpire the side-line really well.
If a line umpire cannot decide a stroke on his own line—as when a player comes between him and the ball, or for any other reason—give your own decision, if you are sure that you could see the stroke; if not, direct it to be played again.
If the same thing happens on one of the lines that you are taking yourself, you can appeal to one of the line umpires, if he is in a place where he could see the ball. On no account appeal to the gallery, for you are certain to get both decisions.
If one of the players in a case of doubt tells you that he lost the stroke, you should take his word for it, as he is almost certainly right. You have no right to ask him, and he is under no obligation to say anything, but if, of his own accord, he gives the stroke, I can see no reason why it should be played again.
If the players agree, their decision should certainly be taken.