I never play World Conquest, I usually go for the space race. But what I have learned from my time here at CFC, go for Howitzers or spies, depending on your money level and/or government. If I would go for Conquest, I'd switch to Communism first, so I won't have to go for peace (I always get UN, so I get a 50/50 to get on)
Anyway, the AI is stupid as h*ll. As I pointed out in the AI Stupidities thread, the AI first wants tribute, even when you are miles ahead technologically. Of course you refuse to pay, so the AI declares war. Then you take one of its cities, and it begs for peace.
Of course that's not a problem if you want to wage war, but their constant beggings for peace really p*ss me off.