How do you beat a Blackjack dealer?

To ultimately win you get blackjack which is a ten or a picture card with an ace (adds to 21)... but otherwise you have to get more and more cards until you get to 21 but you can sit on anything like 18, 19, 20.... as long as you have a better score than your opponent :)

If you're asking how to get an advantage over the house, you have to be card counting.