~What Constitutes a Game

There are 13 cards in each suit; therefore, there are 13 tricks in the play of each hand. A trick is completed when all players have played to a particular lead. The highest bid is seven; we start with a base (called a book) of six tricks. A seven-bid would obligate you to catch all 13 tricks.

Tricks in a minor suit (clubs and diamonds) count 20 points each.
Tricks in a major suit (hearts and spades) count 30 points each.
The first Notrump (NT) trick counts 40 points; all other NT tricks count 30 points each.

A game is 100 points. A game bid is a bid of enough tricks to add up to 100 or more; the bid must be made to earn the points. To add up to 100 (bid and made) takes
~3NT (40+30+30)
~4H/S (30+30+30+30)
~5C/D (20+20+20+20+20)

In contract bridge or party bridge, the 100 points do not have to all be earned in one hand. You may bid and make 2S on one hand and earn 60 points (called a part-score). On a subsequent hand, you need only earn 40 more points to complete the game. The 40 points could come from
~1NT (40 points)
~2H/S (2 x 30 = 60)
~2C/D 2 x 20 = 40)

If you bid 3H, you must take 9 tricks to make your bid (Book + 3 = 9). If you catch less than 9 tricks following your bid of 3H, you are deemed to have gone set, you do not earn any points, but the opponents earn points for setting you.