This section is from the book "Facts Worth Knowing", by Robert Kemp Philip. Also available from Amazon: Inquire Within for Anything You Want to Know.
26. Each person ought to lay his card before him; and if either of the adversaries mix their caros with his, his partner may demand each person to lay his card before him, but not to inquire who played any particular card.
These laws are agreed to by the best judges.
2094. Leader - 1. Begin with the suit of which you have most in num ber; for, when the trumps are out, you will, probably make several tricks by it.
2. If you hold equal numbers in different suits, begin with the strongest because it is the least liable to injure your partner.
3. Sequences are always eligible leads, as supporting your partner without injuring your own hand.
4. Lead from a king or queen, rather than from an ace; for, since the adversaries will lead from those suits which you do not, your ace will do them most harm.
5. Lead from a king rather than a queen, and from a queen rather than from a knave; for the stronger the suit, the less is your partner endangered.
6. Lead not from ace queen, or ace knave, till necessary; for, if that suit be led by the adversaries, you have a good chance of making two tricks in it.
7. In all sequences to a queen, knave, or ten, begin with the highest, because it will frequently distress your left-hand adversary.
8. Having ace, king, and knave, lead the king: for, if strong in trumps, you may wait the return of this suit, and finesse the knave.
9. Having ace, queen, and one small card, lead the small one; for, by this lead, your partner has a chance to make the knave.
10. Having ace, king, and two or three small cards, play ace and king, if weak, but a small card, if strong in trumps, you may give your partner the chance of making the first trick.
11. Having king, queen, and one small card, play the small one; for your partner has an equal chance to win and you need not fear to make king or queen.
12. Having king, queen, and two or three srnall cards, lead a small card, if strong, and the king if weak in trumps; for strength in trumps entitles you to play a backward game, and give your partner a chance of winning the first trick; but, if weak in trumps, lead the king or queen, to secure a trick in that suit.
13 Having an ace, with four small cards, and no other good suit-, play a small card, if strong in trumps, and the ace it weak; for strength in trumps may enable you to make one or two of the small cards, although your partner cannot support the lead.
14. Having king, knave, and ten, lead the ten; for, if your partner hold the ace, you have a good chance to make three tricks, whether he pass the ten or not.
15. Having king, queen, and ten, lead the king; for, if it fail, by putting on the ten, upon the return of that suit from your partner, you have a chance of making two tricks.
16. Having queen, knave, and nine, lead the queen; for, upon the return of that suit from your partner by putting on the nine, you will, probably, make the knave.
 
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