On the game demo's and stuff, it doesn't come up with how to play poker, blackjack. etc.

I don't gamble in real life, I think it's silly, but in FNV It would help me earn money.

Any hints/tips in-game?

Let's use this thread which already has a bunch of tips in it

http://www.gamesas.com/index.php?/topic/1119660-blackjack-jargon