But that's day to day life. When wargaming, something different is called for.
As I've said in other threads at other times, I've been a history buff to the extent that studying history is about as much fun for me as any of my wargaming. I've mostly focused on Medieval History but lately I've gone classical, and the subject of my most intense study has been Alexander of Macedonia, the greatest military commander the world has ever known. (Yes, my youngest son is named Alexander in honor of this man. I admit this freely.)
I was recently overwhelmed with awe at a study of his victory at Gaugamela and the out-of-the-box thinking that allowed an army of 50,000 Macedonians to defeat a Persian army estimated to be anywhere from two to five times its size. For a very interesting video on the battle, take a look at this: Alexander the Great - Ultimate Battles
And so, when standing at the wargame table, with my opponent on the other side presenting me with a tactical problem, there's really only one question:
What Would Alexander Do?
We have been running a campaign for the last couple of years in Warhammer (which I've mentioned before) and there was only one player who was undefeated in the campaign... and I was playing him last round. He'd beaten me before, but it was payback time. And so, as his horde of chaos warriors came across the table toward my gallant knights? I asked myself "What Would Alexander Do?"
He'd set up to look like he was going to do exactly what his enemy expected, and then surprise him with sudden, unexpected cavalry strikes.
... and it worked.

I don't say this to brag. I say it because I've noticed a sad trend in gaming where people spend so much time looking at army lists and reading stats and doing math than they do thinking about tactics. Read fewer army lists. Read more Sun-Tzu. Tactics, not numbers. As long as my opponents keep fixating on numbers and not on tactics I'll drive them off the table every time. It's the tactics that win, not the stats. I don't regard myself as much of a tactician, but even simple tactics will always win against someone who isn't using tactics at all.
Don't ask "What units are best from this book?" Ask yourself "What would Alexander do with all of these units?"
In a recent game my opponent's Dark Angels (Space Marines) had a brand new rulebook with power creep and awesome stats, heavy hitting units and lots and lots of special abilities. My Black Templars (Space Marines) are running a book that is 10 years old and don't get much for their points. How do I defeat a superior army?
What would Alexander do?
He'd leverage his strengths against his opponent's weaknesses and drive a lever into the crack. Victory was so one-sided that my opponent conceded at the beginning of the 3rd turn. Warhammer 40,000 is a 6+ turn game.
Put away the army list. Read Sun-Tzu. Put aside the stats. Read Arrian.
Any fool can win a game with superior units. Win with inferior ones. Win whether your units are better or not. Win because you're a general, not a mathematician. Let the credit for your victories be YOURS, and not the guy's who wrote the rules you exploited to get there. Don't do what the ordinary gamer would do.
Do what Alexander would do.