I used to love playing Blackjack, Here in the UK it is also known as "Pontoon" but don't ask me why? As others have said the best hand to hold is Ace/ Ten, because all picture cards count as Ten, and the Ace can be used as 1 or 11.
When you are dealt two cards at the beginning of a hand, Ace and any Picture card gives you a natural 21, therefore the only way you can lose with it is if the dealer also makes 21, but you don't actually lose if this happens, because it is known as a "Push" and you get your stake back.
If you should win with a natural 21 then you get one and a half of your stake back plus your stake, So a $10 stake you would get your stake $10 + $15 for the win. In
casinos they also have other bets you can make like making a 3 card straight 6,7,8, Which if added up gives you 21, or 3X7s which add up to 21.
Any pair you are dealt can be split, and you double your stake and play the 2 split cards as separate hands, each card will be dealt another card, so basically you are doubling your chances to win.
There are other rules like if you have 11 or under with the first two cards like 6+5 you can "double down" which means you double your stake and the next card completely stops the hand, if you should beat the dealers hand you double your stake back.
The whole object of the game is to beat the dealer, and if you do, you double your money back every time you win. If your hand is beaten by the dealer then you lose your stake. Drawing equal to the dealer at any time is treated as a "Push" and you get your stake back.
Quite a simple game when you get to understand it , but there are little tricks, you can use like as a Punter you are allowed to "Stick" at any time, meaning no more cards are dealt to you. So if you see a 3 in the dealers hand and you think the hidden card could be a ten, you are allowed to Stick but if the dealer has a hand under 16 he has to draw another card which could "Bust" his hand (Going over 21). And you win because the dealer went Bust.
If you go over 21, then your hand is Bust and your stake is lost, even before the dealer has to finish his hand with any other players at the table, It doesn't matter if he goes Bust because you busted before him.
I hope this helps you, but as others have said playing on-line with play money gives you the opportunity to learn the game before you hit the Casinos!
Good Luck!