Surely a player of your bridge skills is familiar with most or all of the following tips you are about to read. But is your partner?
Tips 10-20 are bidding tips.
11. A 2NT response to a takeout double shows 10-12 HCP and is not forcing. A 1NT response to a takeout double shows 6-9 HCP similar to a 1NT response to an opening bid. Notrump responses to a takeout double guarantee at least one stopper (hopefully two), in the opponents’ suit.
You hold: 
KJ9x 
xx 
Q10x 
Jxxx (or AJxx)
West North East South (you)
1 Dbl. Pass ?
With the Jxxx, respond 1NT. With the AJxx, respond 2NT. You don’t need stoppers in the other suits. Partner is supposed to have them for the double.
12. If you play ‘five-card majors’, a short diamond should only be opened with 4-4 in the majors, three diamonds and two clubs.
The incidence of a 1 opening bid with this exact distribution is less than 3%. Translation: When partner opens 1, assume partner has four or more diamonds.
13. After partner opens the bidding and second hand overcalls 1NT to show the strength of an opening 1NT bid, double for penalty if you have 9 or more HCP. Bidding a suit denies the strength to double.
You hold: 10x KJxx AJxxx J10
North East South (you) West
1 1NT ?
Double. You have them outgunned. You should be able to defeat 1NT easily. If you bid 2, you are showing fewer than 9 HCP with at least five diamonds, usually six.
14. It is dangerous to count extra points for short suits or long suits before the bidding starts.
If partner bids your short suit, that reduces, not increases, the value of your hand. If one of your opponents bids your long suit, that decreases, not increases, the value of your hand. If you let the bidding develop, you will see whether your long or short suits are working for or against you.
You hold: Axxx x Qxxxx xxx
What is this hand worth? If partner opens 1, it is a minus 6-point hand. If partner opens 1, it is a 9-point hand (3 points for the singleton with four-card support). If LHO opens 1 and partner overcalls 1, the Q has lost it’s value not to mention the fifth diamond. You are now looking at a minus 4-point hand! Be patient with distributional evaluations until you hear the bidding.
15. It is dangerous to use Blackwood holding a void. If you are missing two aces and partner shows one ace, you won’t know which it is. It is usually better to cuebid when interested in a slam. Also, when responding to Blackwood, do not count a void as an ace. With one ace (or three) and a void, jump to the six level of the void suit if it is lower ranking than the trump suit. If the void suit is higher ranking than the trump suit, jump to the six level of the trump suit. With two aces and a void, respond 5NT.
16. When responding to an opening bid with two four-card majors, respond 1 and give partner a chance to rebid 1. If partner doesn’t rebid 1, assume partner does not have four spades and bid accordingly.
You hold: AJxx KQxx Jx xxx
Partner You
1 1
2 ?
Rebid 2NT and limit your hand to 11-12 HCP. Do not rebid 2. Partner does not have four spades.
17. When the opponents bid and support each other and you have the jack or queen of their suit, do not count points for those honors. They are not worth the cardboard they are printed on.
Secondary honors may take tricks on defense, but seldom do when you are the declarer.
18. When all your honor cards are in your two long suits, add 1 extra ‘purity’ point.
You hold: AKJxx KQxx xx xx
All your high-card points are in your two long suits, so add 1 extra point to your hand. Think of having 14 points. If partner supports spades or hearts, your hand increases in value. If partner does not have support for either suit, your hand stays at 14 points. Hands that have eight-card fits or longer add extra distributrional points. Until the fit is uncovered, distributional points should not be added. It doesn’t make sense. Hands that are misfitted should not add extra points, they should subtract points!
19. When RHO uses Stayman and you, fourth hand, have five clubs or six clubs headed by three of the top five honors, double to alert your partner you want a club lead against any eventual contract. A double of an artificial bid is a lead directing double.
You hold: xxx xx xxx AKJxx
West North East South
1NT Pass 2 ?
Double. You want a club lead against any eventual contract the opponents may land in. Do not double with club length (Kxxxxx) unless you have the necessary honor strength.
20. Also use the lead-directing double when the opponents go through Blackwood. If the response to 4NT is a suit you want led, double! Important!
You hold: xx xxx KQ10x xxxx
West North East South (you)
1 Pass 2 Pass
3 Pass 4 Pass
4NT Pass 5 ?
Double 5 to alert partner you want a diamond lead against an eventual spade contract. At the four level or higher a double of an artificial bid can be made with a strong three or four card suit (KQx(x), KJx(x)). If you don’t double 5, partner will make a negative inference that you didn’t want a diamond lead.