: A, K, Q, 8, 7, 5, 4, 
: 3, 2, 
: 4, 3, 
: J, 5,The Opening Lead in No Trump. The only time opening leads are really easy is against a notrump contract. The general rule is: lead the fourth highest card from your longest, strongest suit. That is, lead the fourth highest card from your longest suit; if two suits are tied in length, lead from the stronger one. The only exception to this is if the top three cards in that suit are in sequence. For instance, with:
: A, K, Q, 8, 7, 5, 4, : 3, 2, : 4, 3, : J, 5,
you should lead the A instead of the 8 You can see that if you just play the ace, the king, and then the queen, you might actually take the other 6 spades, and then your 8, 7, 5, and 4 will all win.
Don't Lead Trump. If you're playing in a suit contract, you should probably not give trump as the opening lead. This is because usually the declarer will want to play trump anyway, so why do his work for him?
Lead from AK. The best lead you can make is to lead one of your top cards from a suit in which you have both the ace and king. This will let you win a trick, without giving up a trick, and will let you see dummy before you lead again, so you can make a more intelligent choice the next time.
Lead in partner's suit. If your partner made a bid in the auction it is probably good to lead the suit she bid.
Lead a singleton. If you have low, useless trump (which you usually do) but you have a singleton in a side suit, it is probably a good lead to lead your singleton. This way, your partner might win the opening trick and lead the suit back to you, which will let you win a trick by ruffing, something you probably won't get to do if declarer plays his high trumps.
Never underlead an Ace. It is, generally, pure foolishness to lead a low card from a suit in which you hold the ace. If you do, you may give declarer a free easy trick with a medium honor like a jack or 10, and you may also not be able to take your ace later, if declarer or dummy had a singleton. If you ever have to lead from a suit with the ace and some lower cards you should lead the ace... but this usually creates a free trick for declarer so you should avoid it.
Lead the top of a two-card sequence. If you have a suit headed by the KQ or the QJ, leading one of the top cards is good because it helps promote your lower card.
Lead the top card of a doubleton, particularly if it is an ace. In this situation, you can maybe set up for ruffs in that suit. If you have an ace-small doubleton, leading the ace followed by the small card is pretty similar to leading a singleton, which makes for a good lead. Other doubletons are reasonable leads as well, but if neither you nor your partner wins the first trick it will probably have been a waste of time.
Avoid underleading an honor. Try not to lead a small card from under your J, Q, or K in a suit either. It's not as bad as underleading an Ace, but it is likely to make your honor not win a trick.
Lead dummy's suit. If you want to make a safe lead, lead the suit that dummy bid during the auction (except for trumps). That way, you can at least be pretty sure you won't be trapping your partner's high cards in front of declarer's high cards.
Which card to lead in a suit. If you are going to lead from a suit with the Ace, lead the ace (though many players lead the king from the A-K, as a signal to their partner). If you are going to lead from a suit headed by a sequence of at least two cards (J-10 or better), lead the top card. Otherwise, lead the lowest card in a 1-, 3-, or 4-card suit, the high card from a 2-card suit, and the 4-th highest from a 5-card or longer suit.
Defending in no trump. Whenever you get the lead in no trump, lead the suit that was originally led by you or you partner. The idea is for you to set up the small cards in that suit for extra tricks; you are unlikely to have the high cards to set the contract without doing this (though it is possible).
Second hand low, third hand high. If you are the second player to play a card on a trick (ie, declarer or dummy led), and you are deciding between playing an honor and playing a low card, you should play LOW. If you are the third player, (ie, your partner led), you should play HIGH. Of course, you shouldn't play your high card if it's not going to at least be the highest card played so far...
Cover honors. As an exception to the above rule, if you are playing second, and the first card is a high card but you can beat it, you should. In a sense, this way your honor isn't wasted. If you play a king on a three, only to have it taken by the ace, this isn't much good, because you both used one honor but declarer got the trick. On the other hand, if you play a kind on a queen, and have it taken by the ace this is good: declarer used two high cards to win the trick while you only used one on it.
Lead through strength If you are on lead and dummy is to your left, you are better off leading a suit in which dummy has some of the highest cards left. This way declarer will have to decide whether to use them before your partner does.
Lead up to weakness If you are on lead and dummy it to your right, a good lead is one in which dummy is weak (especially nice is if you can actually play a higher card than dummy has). This way, once again, you are playing through strength.
Don't give a ruff and sluff. If you are on lead, do NOT lead a suit in which both dummy and declarer have no cards left. If you do, this almost certainly gives declarer an extra trick. In fact, generally speaking, don't lead a suit which dummy can ruff: if you never do, declarer will never get a ruff and sluff. It's better if you have to choose one, to lead a suit where declarer will be able to ruff in his own hand and not in dummy.
For the time being we will focus on only four things in the play of the cards: winning with high cards, promotion, finessing, and drawing trump. The first three of these deal with how to win tricks playing in a particular suit, while the last one deals with which suit to play. The last one is simple so we might as well get it out of the way.
In a suit contract, draw trump right away. What "drawing trump" means is that you should play trumps for as many tricks as possible, and keep playing trumps until the opponents have no more trump cards left. This means you will have to COUNT. Counting is indispensible in bridge. Remember there are 13 trumps in all. Keep track in your mind of how many have been played, and how many you have left. Whatever is left over after those is the number of trumps the opponents have. The "right away" part of this guideline is the important thing. If you have a good reason for not drawing trumps right away you can put it off, but you should never do it without a reason.
Okay. Now, we will discuss some simple ideas about how to maximize your tricks in a given suit. There are three simple techniques - winning high cards (which is very easy), promoting high cards (which is almost as easy), and finessing (which is a little tougher).
Winning high cards. If you want to win a trick with a high card you can either lead it, or lead a low card in the same suit to win it when the lead and the high card are in opposite hands. There really is nothing to this. But to highlight the importance of drawing trump: if you are in a suit contract, the only way your high cards can fail to win a trick is if they are trumped. If you have drawn trumps this cannot happen. Therefore you can RELY on your high cards to win. That said, one of the pitfalls with high cards is that one looks at them as free tricks when planning. You should remember that you have to actually manage to play them, so when you are planning the play you should think about the order in which to take your high cards.
Promoting high cards. Suppose you have a suit with the following cards: K, Q, J, 10, 9. You don't have the ace, so none of those cards will be guaranteed to win the trick. However, if you just play one, and the ace takes it, the other four will be high, and you can win them: they have been "promoted" from almost high cards to high cards. In fact, holdings like K, Q, J, 10, 9 are magnificent because they guarantee to set up. With a sequence like this you should consider promoting your high cards. You can also lead towards a sequence like this to promote high cards. A final example. You have in your hand: K, Q, 4, and in dummy you have J, 5, 3. You can win two tricks in this suit by promotion just as you would if the high cards were all in the same hand: you lead one (or to one) and when the ace takes it, the others are high.
By the way, what if the opponents held off the ace? It wouldn't help. You would still win all but one of the tricks (provided they EVER get to play their ace), just like you wanted. Another kind of promotion is where there is more than one high card to get rid of. For instance if you had Q, J, 10, 9, you could play one to force out the Ace and the next one to force out the king, leaving your last two cards high.
Finessing. Suppose now that you have K, 4 in your hand, and dummy has the 3, 2. How can you win a trick? Not by leading the king, surely... then whoever has the ace will win it and your other cards are as low as they can go. However, you do have a chance. Suppose you lead the 2 from dummy, and the ace is on your right. Then you will win your king! If they play the ace on the 2, your king is now high and will win later. If they do not play the ace, you play your king now and it will win now. On the other hand, this strategy will give you no tricks if the ace is on your LEFT, but at least you have a chance. There are many forms of the finesse. Another example: You have the A, Q in your hand, and the 3, 2 in dummy. If the king is on your right, you can lead the 2 from dummy; if the king comes out you take it with your ace, and if not, you win your queen.
Suppose you have the A, Q, 10 in your hand, and the 4, 3, 2 in dummy. You are only sure of one trick, but you have a very good chance of being able to get two! Lead the 2 from dummy. If the right hand player plays a jack, play your queen. If the left hand player wins, your 10 and A are high cards. If not, your queen wins, and you ace will also win. If the right hand player plays a king, play your ace. Now your queen is high. Finally, if the right hand player plays low, play your 10. If the left hand player wins with his jack, you can try the finesse again once you get back to dummy. If the left hand player wins with the king, though, your ace and queen are now high and you win them both. This method of play will give you 2 tricks unless BOTH the king and jack are on your left. By the way, it will actually give you 3 tricks if they are both on the right!
Another form of the finesse is where you have the A, 3, 2 in your hand and the Q, J, 10 in dummy. Now it's easy to get 2 tricks; you play your ace, then over to your queen, forcing out the king to promote your jack. But you can actually get all three tricks if the king is on your right. Play the queen from dummy. If the king comes out, win the ace: now your jack and 10 are good. If not, play low. If the king is on the left it will win now, but you had a chance. Another interesting form of the finesse: you have A, 10, 2 in your hand and Q, J, 3 in dummy. You could lead low from dummy and then finesse as usual in your hand, but this has a disadvantage: if you win with the low card in your hand you'll have to go back over to dummy with another trick to finesse again. So, it's best to lead the Q from dummy, letting it ride if it's not covered. This way, if the king isn't drawn out and the queen wins you can try the finesse again right away. But you should watch out: the J in dummy is important. Suppose instead that you have A, J, 2, and dummy has Q, 4, 3. Now, you play the queen, the right hand player plays the king, and you take your ace. Your jack is now high, but that only makes two tricks. In this position, you should play low from dummy.
The final form of the finesse we'll talk about is the bi-directional finesse. In this one, you can actually finesse in either direction. A typical setup: you have A, J, 5 in your hand, and K, 10, 3 in dummy. You can finesse from either hand: lead the 5 towards the K, 10 split (these pairs of honors with a gap between them are called "tenaces"), or lead the 3 towards the A, J. Here's a neat trick to try - many beginners, when they are being finessed successfully, will think about whether to play their honor or not. If they sit and think about it, it gives away that they have something to think about. If they had no high cards, they'd just play one of their low ones. If your opponents are like this, a bi-directional finesse can be very nice. Start, for instance, by leading the 3 towards your hand. If your right hand opponent thinks, and plays low, play your jack. Probably you will win your jack, and your ace and king are still high. On the other hand, if your right hand opponent comes out quickly with a low card, play your ace. Now you figure that player probably DOESN'T have the queen, so you play the 5 from your hand and finesse the OTHER player. This can lose, of course, if the player on your right just plays a low card quickly when he has the queen, but chances are pretty good he won't sit around thinking when he DOESN'T.
Starting to sound pretty advanced, huh? Well, it gets a lot tougher than this. Finesses are great tricks to have up your sleeve, but expert players use them only (1) in emergencies, (2) for extra tricks, or (3) to see if it succeeds, in which case their contract might be easy to make. In the mean time, deal out a few pairs of hands and see how many tricks you think you could make playing them as declarer.