One game of Blackjack followed from the deal to the finish, move by move, with the reason for each choice.
You are playing alone against the dealer with the table's standard rules: 200 chips, a minimum bet of 10, and a dealer who stands on soft 17. Here are four rounds, each with a different decision in it, all bet at the minimum of 10.
In every round you see both your cards and one of the dealer's. The dealer's second card stays face down until you have finished.
You are dealt 7♠ 4♦, a total of 11, and the dealer shows 6♣. This is the best spot in the game to double: any ten-value card gives you 21, and a dealer showing a 6 is the dealer most likely to bust. You double, putting another 10 on the hand, and take your one card — 9♥, for 20.
The dealer turns over 10♦, making 16, and must draw below 17. It draws 8♠ and busts with 24. Your doubled bet wins 20, and you have 220.
You get 8♥ 8♣ against the dealer's 10♠. As one hand that is 16, the worst total there is. Split, the two eights are two fresh starts, so you put up a second bet of 10. The first eight is dealt 3♦ for 11, and a split hand may still be doubled, so you double it and draw K♣: 21. The second eight is dealt 10♥ for 18, and you stand.
The dealer's hidden card is 7♠, a total of 17, and it stands. Both your hands beat 17: the doubled 21 wins 20 and the 18 wins 10. You now have 250.
The dealer shows A♦, so before anything else you are offered insurance. You decline: it is a side bet that loses in the long run. The dealer does not have blackjack, so play goes on.
Your cards are A♠ 6♦, a soft 17 — the ace counts 11 for now, but it will drop to 1 rather than let you bust. Against an ace, soft 17 is a hit. You draw 5♥, and the ace becomes 1: a hard 12. You hit again, draw 7♣, and stand on 19. The dealer has A♦ 5♣, a soft 16, and draws 10♦ for a hard 16, then 3♥ for 19. It is a push, and your 10 comes back. Still 250.
You have 10♣ 6♠, a total of 16, against the dealer's 9♥. Standing on 16 against a 9 loses most of the time, so you hit — and draw Q♦ for 26. You have bust, and your bet is lost at once.
The dealer does not even need to play its hand for you: going over 21 loses whatever the dealer would have made. That order of play is where the house edge comes from. You finish the four rounds on 240, up 40 on where you started.
The good results came from the decisions that put more chips in when the odds were best — a double on 11 and a split of eights with a double after it. The push and the bust were both correct plays too; blackjack is played on the long run, not on one round.
Every one of these decisions followed basic strategy for a dealer who stands on soft 17, which is the default at this table.