Memorize the following rules. If you’re dealt a pair, do whatever the first set tells you. If you aren’t dealt a pair, and for all subsequent cards, do whatever the second set tells you.
Pair of 2’s - Split against 3 through 7, Hit against everything else.
Pair of 3’s - Split against 4 through 7, Hit against everything else.
Pair of 4’s - Double down against 5 or 6, Hit against everything else.
Pair of 5’s - Hit against 10 or A, Double down against everything else.
Pair of 6’s - Split against 6 or lower, Hit against 7 or higher.
Pair of 7’s - Split against 7 or lower, Stand against 10, Hit against 8, 9, or A.
Pair of 8’s - Split.
Pair of 9’s - Stand against 7, 10, or A. Split against everything else.
Pair of 10’s - Stand.
Pair of A’s - Split.
Soft 16 or less - Double down against 4, 5, or 6, Hit against everything else.
Soft 17 - Double down against 6 or lower, Hit against 7 or higher.
Soft 18 - Double down against 3 through 6, Hit against 9 or 10, Stand against everything else.
Soft 19 - Double down against 6, Stand against everything else.
Soft 20 or 21 - Stand.
Hard 7 or less - Hit.
Hard 8 (2 & 6) - Hit.
Hard 8 (any other) - Double down against 5 or 6. Hit against everything else.
Hard 9 - Double down against 6 or lower. Hit against 7 or higher.
Hard 10 - Hit against 10 or A. Double down against everything else.
Hard 11 - Double down against everything.
Hard 12 - Stand against 4, 5, or 6. Hit against everything else.
Hard 13 through 16 - Stand against 6 or lower. Hit against 7 or higher.
Hard 17 or higher - Stand.
Never buy insurance.
If you follow these rules all the time, you’ll lose very slowly. Which is the best you can expect in any gambling game.