For a few years of my life in the late eighties/early nineties, I could often be found in Las Vegas. A hotel room there seemed like a better place to do binge writing when I had a lotta scripts to finish. I had a lady friend who was dancing there, usually in Lance Burton's show at the Hacienda, and I had a lot of "comps" for free hotel rooms and sometimes food because I was playing a lot of Blackjack.
With the aid of several different books, I taught myself how to count cards in that game. In over fifty trips to that city (and a few to Laughlin or Reno), I never once played Roulette or Keno or Poker and I honest-to-God still do not know how to play Craps. I pulled a few slot machine levers and would occasionally do a little Video Poker but 95% of my gambling was Blackjack because, thanks to card-counting, I could usually win.
I did not win a lot. Only once did a casino ever ask me to take my "action" elsewhere…and that was a time when I was winning due to sheer luck and not because I was counting. It was just one of those wonderful streaks that can and does happen to anyone occasionally. The dealer lady was just dealing good cards to me and bad cards to herself.
At the level I played, I was probably earning more-per-hour for the time I spent up in my room on the laptop than when I was in the casino. Counting cards was just something I did to see if I could do it and once I mastered the skill, I didn't have to do it anymore. I have been to Vegas a lot since then but I have not played Blackjack in this century. I doubt I could do it today without a lot of study and practice, practice, practice.
It's not easy. You have to do a lot of math in your head and not get distracted. My brain tends to roam wildly from topic to topic so I needed a lot of focus. You also have to look at everyone's cards without making it too obvious that you're looking at everyone's cards…and when the count goes way up and you raise your bets way up, you have to act very casual about it, like it's a whim and not a calculated strategy. Since I quit, I've had zero desire to subject myself to that anymore.
And like I said, I don't fully remember how to do it. Ah, but I just came across this video which in five-and-a-half minutes, explains the basics of the particular counting system I employed. There are others but the way this guy does it is pretty much the way I did it, except that back then, I could usually find a good double-deck game, meaning that the dealer dealt from a double-deck (104 cards) instead of like today when they employ a five or six-deck shoe — 260 cards or 312. Counting is more effective with the smaller number, especially when you could find — as you can't anymore — dealers who dealt almost all the way down, close to the end of the deck before they shuffled.
You may not be able to follow this and there's much more to learn than this, but here's the method that worked best for me…