Suppose you, being elder hand, receive queen, ten, nine, eight, and seven of clubs, knave, ten of diamonds; king, queen and knave of hearts; ace and nine of spades, the natural impulse would be to retain the clubs intact for the point and sequence, and discard from the other suits. But Hoyle recommends you to discard all the clubs. It is true that if you took in the knave of clubs it would be a good thing, but it is three to one against it, whereas, if you keep the other suits intact, you will take in something that will give you a better chance of scoring than you could have made by the other course.
It may assist your discard to consider, by inference from your own hand, what the adversary can or cannot possibly hold. For example, if you are very short of a suit, he may have a long point or sequence in it. If you have any honour or ten, he cannot hold a quatorze of that rank, but if you are short of one, he may do so; also your holding a knave or ten, or some other combinations, will prevent him from holding a quint in that suit, and so on.
Beware how you unguard kings and queens. If, being elder hand, you reject a guard to a king, it is probable that in taking five cards you may replace it; but when you are younger hand, it is highly desirable to retain the guard, and for this purpose it is considered further advisable to keep a small card of a bad suit, that it may serve as a guard for a king if you should take one in.
In some positions you must regulate your discard according to the score. Thus, if you only want a few points, it would be foolish to lay out with a view to any large object; you would devote all your attention to what counts first, namely, the point and sequences; success in which might carry you out before your opponent could get in. On the other hand, if your adversary is much in advance of you, you can probably only retrieve your fortune by a large score, and you would discard with this view. To consider the "cards," unless with a view to a capot, would be useless.
It is considered desirable for you, if elder hand, to take all five of your cards, unless you have a chance of a great score, and there can be no repique against you. The consideration is not only whether the cards will benefit you, but also whether, if you leave them, they may not much more benefit your adversary.
If the younger hand should have dealt to him a hand which will enable him to make six tricks, Hoyle advises that he should not make such a discard as will incur the risk of losing the "cards," unless he should be very backward, and have a scheme for a great game.
In regard to the play of the hand, it is difficult to lay down rules, but an acquaintance with Whist play will be a very useful general guide to the student, showing him how to establish and bring in his suits, how to get tenaces led up to, how to preserve guard to second-best cards, and so on.
The most essential thing is to secure the seventh trick, which scores the "cards"; though, of course, every trick made is of importance to your score, the last counting two.