Most game changing concept/tip

I've gotta say the despotism penalty. I was always confused why tile yields didn't match up with th civilopedia. "Why does the civilopedia say cattle is +2 food, but it only seems to provide +1?"

Understanding the despotism penalty makes so many other aspects of the game make sense.

 

1) When you think you have no options, you have options. For instance, trading your only iron for a big tech payoff. Lots of options in this game if you just take the time to think about them. It is a turn based game.

2) After middle ages, have an even balance of artillery, attacking unit, defending unit. Most of the time this is arty, cavalry and infantry, but it applies with all the newer techs as well.

 

Really. Kept doing the same thing myself, not only for Carrier air but land-based as well. Always wondered why so many Fighters were either lost or didn't attack Bombers on the same turn they were activated for Air Superiority. BTW here's an old thread which reinforces these observations (warspite2 starts talking about Fighters in Cities in Post #11--and Roland Johansen backs him up 6 posts later while adding that AS range is half of the given operational range):

https://forums.civfanatics.com/threads/problem-fighters-not-intercepting-from-carrier.104077/

 

My Eureka moment was just a couple of days ago when I was playing the Play the World scenario of Test of Time, where you have a LOT of very tough naval vessels to deal with. I suddenly realized that instead of sending out galleys one at a time to take on the AI ships, I could send three or four, and suddenly, I was taking down the AI preset ships. The preset ships are all Elite, and I have boosted the combat values for Regular, Veteran, and Elite.