My advice to a beginner is: Be cautious and, until you have learned to value your hand, be satisfied with the number of points you can make without doubling.
ESTIMATING THE VALUE OF A HAND
To determine the probable trick-taking value of your hand, count each Ace and King as a trick, and add to these the number of tricks you can take in the trump suit. Queens count only as possible tricks, as the third round of a suit may be trumped.
In determining the number of tricks you can take in the trump suit you must remember that it makes a great difference on which side of you the trump strength lies. For instance, holding Ace, Queen, and ten of trumps, if you play after the maker, you will probably get three tricks; but if the maker plays after you, your trumps can be led through, and you may make but one trump trick.
If you play after the maker,
| J x x x | of | trumps | are | worth | 1 | trick |
| Q x x | " | " | " | " | 1 | " |
| Q J x | " | " | " | " | 1 | " |
| Q J x x | " | " | " | " | 2 | " |
| K Q x | " | " | " | " | 2 | " |
| K J x | " | " | " | " | 2 | " |
| K Q 10 x | " | " | " | " | 3 | " |
| A Q 10 | " | " | " | " | 3 | " |
| A 10 9 7 2 | " | " | " | " | 3 | " |
RULES FOR DOUBLING
To double spades, you should hold in your hand 4 tricks and a possible 5th.
To double hearts, diamonds, or clubs, you should hold five tricks and a possible 6th.
To double "no-trumps," you should hold 6 tricks and a possible 7th.