The only time that it seems right to me to cross is when there has been a very weak return made, and you feel sure that you can kill the ball, and at the same time feel sure that your partner is too far back to reach it in time to do the same thing.
With this exception, never go in front of your partner; it destroys his confidence, and he never knows when he will be called upon to play.
There are a great many balls between the two players which one of them can certainly play better than the other, and yet the wrong one will often take them. In such cases it is simply a mistake; it is not poaching in the real sense of the word. One often takes such balls instinctively, and often, too, one is a bit farther forward than one’s partner, and cannot tell if it is safe to leave the balls to him.
There is certainly a lot of poaching done, and a sufficient reason for avoiding it is that it really does not pay.
On the other hand there is a lot of nonsense talked about poaching, where it is simply jealousy between the two players.
When a player cannot forgive his partner for taking a ball that he should have left to him, especially where it is simply a mistake of judgment, he is not himself a fit partner to play with.
Another great mistake is to find fault with your partner’s play. It never does any good, and it either makes him lose his temper or discourages him. If he misses an easy stroke, remember that you might have done the same, and if he makes a good one give him the credit of it.
If your partner is going to play a stroke, keep away a little and give him room. If he hears you coming up behind he may think that you mean to take the ball, and, in any case, hearing you so near may take off his attention.
Be careful to play up as well as you can all through a double match. You may be able to pull yourself together after some slack play, but you may have got your partner so discouraged that he cannot play at all, so that you will lose the match and it will be nobody’s fault but your own.
This applies also in cases where your partner lacks endurance. Remember that he may be of little assistance to you at the end of a long match, and you should never by any carelessness of your own, give your opponents a chance to prolong the game.