Sometimes you hear about people getting busted for counting cards at blackjack (AKA 21) and it can be confusing, because there not literally counting cards. They do this thing that helps them win, and every 21 player should do it too!
To count cards all you need is a system of card counting and some cards and a casino to practice your counting. One way is to keep track of how many good cards have been dealt using counting systems that dont use regular numbers to count but use a lo-lo-hi-hi formula to see if you should go all in on a bet.
Casino pit bosses dont want to see people counting cards at a table so they will tell you to stop counting cards if they know you are counting cards. You can even get kicked out of las Vagas if you do it too much! So practice at home counting inside your head and not mumbling or using your fingers because then the jig will be up!!!! Oh yeah, Ben Affleck just got busted for this so be careful!!! LOL!!
So know you know how to go to a casino in Vagas or maybe Atlantic City (if your poor) and come away with a lot of extra winnings in your pocket!