Beating the AI at Diety in Civ II wasn't always easy either. There are some strategies that are key, like the Super Science City, We Love The Consul Day, the Democracy/Freight combo, and Infinite City Sprawl. There are also Wonders that, it turns out, are pretty much cruicial. I expect it took more than a month or two of playtesting to figure these strategies out. I await the wisdom of my fellow Civ keeners in the Civ III Strategies forum!
Beating the AI at Diety is not terribly HARD, perse, it's just incredibly annoying. Basically the civil disorder problems are so severe that it's like flaying yourself slowly to actually play the game through. After I beat Deity a few times I played on Emperor for fun usually.
I have no idea what "ICS" or "Infinite City Sprawl" means because I'm not a board regular, but my basic strategy is always instant expansion -- build several fast units as early as possible and look for goody huts, hoping for free new cities. One of the keys to civ is realizing that creating tons of cities early is usually the best way to get ahead. There are also DEFINITELY wonders that are basically necessary. It's been 1.5 years since I played Civ, but I'm incredibly psyched for civ III. I ordered my copy from Outpost.com and it hasn't shipped yet. Grr...
