In Texas Hold'em, you're always attempting to create the best 5-card hand. In games where you are working with more than five cards, you disregard other cards. Also note that in casino games, suits have no value in ranking hands. So, for instance, if two players have royal flushes, they split the pot. A spade royal flush does not beat a club royal flush.
The following lists the rank of poker hands from the highest to the lowest:
Royal Flush - The strongest hand and it consists of five cards from 10 to Ace which are all of the same suit. While this is a very rare hand they do come up from time to time again in online poker.
Straight Flush - The next best hand and it is five consecutive cards that are all of the same suit. You would be incredibly unlucky indeed if you lost with a straight flush.
Full House - Made up of a pair and three of a kind. In the event of two people both having full houses the person who has the higher card for his three of a kind wins. For example if you have K-K-K-A-A and the other person has A-A-A-2-2 they win.
Flush - Five cards of the same suit. If more than one person has a flush the person with the higher card wins. If the highest card is the same, you go to the second highest card, etc until you find a difference.
Straight - Five consecutive cards. The person with the highest card wins so K-Q-J-10-9 would beat 8-7-6-5-4.
Three of a Kind - If two people have the same three of a kind you look at the next highest card to determine who wins the hand.
Two Pair - Simply is having two different set of pairs.Of all the poker hand rankings two pair is the most dangerous because players tends to be far more aggressive with it then they should.
One pair - Just a single pair.
High Card - Nothing and the winner is determined by who has the highest card.