While there are certain games that call upon alternate use of the hand rankings, such as high-low games, here are the standard ranking of hands, in order of importance, for your edification.
From Weakest to Strongest
The lowest ranked hand.
This occurs when no other hand can be made:
Two cards of the same value, different suit:
Self explanatory:
Three cards of the same value, different suit:
5 cards in sequential order. (In the event two players have a straight, the player with the highest card wins. Aces can be used as either the highest, 10,J,Q,K,A, or lowest card, A,2,3,4,5):
5 cards of the same suit (In the event two players have a flush, the player with the highest card wins):
Three cards of the same value, with a pair. (In the event two players have a full house, the "trips" of highest value wins the hand):
Four cards of the same value:
A straight, all of the same suit:
The best hand in poker, it is the highest straight flush possible:
Some clarification:
When two players have the same hand, i.e., the same two pair, the hand with the highest fifth card, i.e., the kicker, wins the hand:
In this example, the first hand, with the queen kicker, wins.
In this example, the five cards are identical. The pot is split.