Source: Over the past several years I have been compiling information and guidelines which, cumulatively, have assisted me in improving my understanding, expertise and enjoyment, both offensively and defensively, in the playing of the game of bridge. These tips have been gathered from my bridge experiences during competitive play, from books that I have read, and from published articles that I have accumulated.  Bridge Tip #1 
       We have all heard the Bridge axiom, “third hand plays high.”   Do NOT play third hand high, however, if it will benefit only the Declarer. 
In a suit contract, Partner will usually not lead a low card when holding the Ace in the suit he/she has led.   Therefore, knowing that the Declarer holds the Ace may enable you, as third Player, to deduce that playing high in third seat cannot win the trick and will only establish winners for either the Declarer or the Dummy.  In such instances, withhold your honor card – there is no merit in playing a high card if it benefits only the Declarer.
KJT98 (Dummy)
Q7632 (You)
West Leads the 5 In this instance, South (the Declarer) holds either the A4 or a singleton A.  Dummy plays the Jack.  If you, as East, play high and cover with the Queen, Declarer will have five tricks.  Declarer can only score four tricks in the suit, however, if you play low.
KT963 (Dummy)
J542 (You)
West Leads the 8 In this instance, if Declarer holds AQ and Partner has led from the 87 doubleton, Declarer is entitled to only four tricks if East plays low but will roll five tricks in the suit if East wrongly covers with the Jack. Bridge Tip #2  Bridge hands holding a 6-5 pattern; i.e., especially when holding a 6-card Minor suit and a 5-card Major suit oft times present the Partnership with difficulty in reaching the correct contract. In today’s 5-card Major bidding systems, Players often forget the adage to, most times, bid length before strength, and are too eager to erroneously show their 5-card Major suit first. Dealer South: Both Teams Vulnerable
NORTH  K 5 Heart Suit 8 7 6 3 Diamond Suit J 8 4 club suit A J 9 2
WEST  9 6 4 3 Heart Suit K 9 5 4 Diamond Suit A 6 club suit Q 10 3 EAST  8 7 Heart Suit A J 7 2 Diamond Suit 7 5 club suit K 8 7 6 4
SOUTH  A Q J 10 2 Heart Suit Q Diamond Suit K Q 10 9 3 2 club suit 5
West North East South
1Diamond Suit
Pass 1Heart Suit Pass 4
Pass 5Diamond Suit All Pass
Jumping to game in a new suit promises five cards in that suit along with game values.
By bidding Diamonds first, as seen above, South evidenced Diamonds, the first suit bid, as being longer (since with two 5-card suits, normally starting with the higher ranking is preferred).   North properly corrected to 5-Diamonds.  Notice that if played in Four Spades, the contract in the hand above is un-makeable as South would be forced to trump Hearts in his/her hand thus defeating the contract, whereas, in Diamonds, the contract proves to be easily made by drawing trumps and merely losing the two red Aces. Alternatively, with a 6-5 distribution of lesser quality than seen above, prefer to start with your 6-card suit and then bid your 5-card suit at the cheapest level, followed by a repeat of the 5-card suit, again at the next cheapest level.  This sequence, unlike the above-referenced bidding, is not forcing and could allow the Partnership to bail out at a low level. Bridge Tip #3  Dealer South: (You): JX  Heart SuitXX  Diamond SuitKQJX  club suitAJXXX  Normally, one bids length before strength.  However, when holding minimum opening values (as in the hand above) specifically housing 4-Diamonds and 5-Clubs, Opener should be very careful to always open 1Diamond Suit, prepared to re-bid 2club suit,even though the Club suit is longer than the Diamond suit. If the opening bidder were, mistakenly, to open 1club suit, Partner is statistically likely to respond 1Heart Suit or 1, just what Opener did not want to hear.   Since Opener would not be able to pass (“A new suit by Responder is almost always forcing for one round.”), Opener would then be stuck for a re-bid.   If Opener were, hypothetically, to respond 2Diamond Suit, this would offer erroneous information to the Responder since it would evidence a “Reverse” bid (the second suit, Diamonds, being higher-ranking than the first, Clubs), and would mislead the Responder in that a Reverse bid by Opener shows a hand equal to 17,or more, HCP’s.    If, alternatively, Opener were to respond 2club suit, this, too, would be almost equally as bad in that it would erroneously promise a   6-card Club suit, or, at the very least, a good 5-card suit, neither of which is present in the above-referenced hand.  The only solution:  Opener should open 1Diamond Suit, prepared to re-bid 2club suit, the best bidding alternative, under these conditions.
Remember: Opener should always consider his/her second bid, before making a first bid.