Before you even sit down at a BJ table, you should 1) know not to play 6:5:shit under any circumstances (ANY circumstances) 2) know Basic Strategy 3) trust in Basic Strategy.
It actually makes the game more fun to simply know what you should do in every situation. Play for more than two minutes and you'll see somebody staring at a hard 16 against a dealer 10 and gritting their teeth and straining as if they were giving birth to a porcupine, trying to divine if the dealer has a large or small card in the hole. The Basic Strategy player just shrugs and hits. He might know that by doing so, you increase your chances of winning from about 24% to about 26%. Still crappy, of course, but 16 is a loser no matter what. But making the proper decision 50 times will eventually save you one bet. All Basic Strategy decisions do that one way or the other.
So WITHOUT looking at a Basic Strategy chart, can you answer the following five questions?
1) Against which dealer upcards do you split 99?
2) Which actions do you take with soft 18 (A7) vs. all the various dealer upcards?
3) When do you double a hard 9?
4) With a hard 12 through a hard 16, you stand against all dealer 2 through 6 EXCEPT in which two instances?
5) Do you ever double with a soft 19 (A8), and if so, when?
If you don't absolutely know the correct answers to all these questions, you have no business playing the game, or at least no business complaining when you lose! (These are not the five most important decisions as such, but the five I've seen that people get consistently wrong.)