I wouldn't bother even trying to count at a casino. The surveillance is so sophisticated that you'd never get away with it. I believe that it is technically legal, since it's not cheating - it's just playing smarter than the house, assuming you do it all in your head. However, they will certainly ask you to leave and relay your info to all other casinos they have access to. I suppose it's better to be blacklisted than kneecapped, but either way the game's over. The house will always have an advantage, but with some basic research and practice, you can cut their advantage to a very small margin. I haven't played in quite some time so I'm sketchy on the particulars, but generally your best bet is in Vegas, especially on the old strip. Binion's is the best IMO. Their rules are slighly more to the players advantage and it is easier with a single deck. I wouldn't even play (seriously) anywhere else, especially not the Indian casinos as they are notorious for offering the worst odds on almost all of their games. Nothing wrong with playing for fun, though. I would try to time my game enterance for when the waitress is coming around with the free drinks.
A couple other games that carry a very small house advantage are video poker (know which payout schedule is best and learn how to play smart) and craps. I learned how to play on a playstation game and read a book called "What Casinos Don't Want You to Know." The most important and most difficult rule to learn for all games is: know when to walk away! Never try to chase your losses. There's a reason that casionos are so fancy and luxurious!