Source: by David Huggett for Mr Bridge
YOU are South as declarer playing teams or rubber bridge. In each case, what is your play strategy?
You are in 3NT and West leads the 
J. East plays the 7. How do you pion the play? Even if the club finesse wins, you still need a heart trick and it might seem as if it doesn’t matter which suit you play on first. But, of course, it does. If you tackle clubs and the finesse loses, East will play back a diamond and you will be defeated every time the diamonds break 5 -2 and West holds the ace of hearts. But, if you knock out the ace of hearts first, then you will be taking the club finesse into the hand with the short diamonds and, if East storted with three diamonds, then all you lose are two diamonds, one heart and a club.
You are declarer in 6
. and West leads the 
Q. How do you plan the play (trumps split 2-2)?
The only possible losers ore one spade and one diamond and it looks as if you just need one finesse to be right in either of those suits. But consider what will happen if you draw trumps and run the jack of diamonds. If it loses, East will return a spade irrespective of his holding and you won’t know whether to finesse or not. If diamonds break evenly, you can pitch three spades from hand, but if they don’t, you will need the king of spades to be on side. You are being put to a premature guess but you con stop all that by drawing trumps and leading a low diamond from dummy. If East plays the king, then you wi ll almost certainly have enough discards for the spades, while if West wins he cannot lead a spade without giving you the contract. The difference now is that you can test the diamonds first.
You are declarer in 4
and West leads the 2. How do you plan the play?
Sometimes, it is hard not to play on autopilot and that could well happen here if you are not careful. Suppose you take the heart finesse instinctively and it loses, then, on a bad day, the defence might manage to come to a club ruff and you will have gone down in a contract that was 100% guaranteed . If you simply play the ace of hearts at trick one and draw trumps, you will find nothing can stop you from coming to ten tricks. It is true that you might lose a heart trick unnecessarily if the king of hearts is well placed, but that is a small price to pay for guaranteeing the contract. 
You are declarer in 4. and West leads the . Q. How do you plan the play?
5 is where you really want to be but 4 is certainly playable, although you do have to be careful. Suppose you win the opening lead, draw three rounds of trumps and find that they do not break. Then, when you play on clubs, a defender will ruff and you will lose three diamonds. The answer is simple – just duck a heart early on. Dummy can take care of a third round of diamonds and as soon as you regain the lead, you can draw the rest of the trumps.