The original Klyden strategy guide had a great way to gain a huge strategic advantage, but I don't think the newer ones do.
Basically? Replace all irrigation with mines. Since food is easy to come by in AoI, your cities will all be large enough to work all tiles, making the excess citizenry useless as there's enough money in the game that any research/tax specialists are also unnecessary. Barring a defensive bonus, the extra citizens don't really have a benefit.
The net result is even if you have a tiny position, you're going to be miles more productive than any of your peers on a per-city basis. Which means those production-enhancing improvements get built quicker, which means you're going to become a powerhouse extremely fast.
I've taken Russian Manchuria and Vladivostok in my USA game and I'm on my way to Chita Oblast... I think I'll go into the saved game editor and make the difficulty higher. I am rapidly approaching the "roflstomp everyone" phase.
Or heck, maybe I'll just declare war on everyone. That's bound to be entertaining.