In preparation for multiplayer, I wanted to go through and win a game under each victory condition. Mainly to understand.  I am a little unclear on how the diplomatic victory is achieved. I know that you need to make someone an ally, but what are the specifics. Research ally technology? How do you achieve a higher relationship? Is it a chain of non-aggression pact, ally, trade child away, then alliance?  I can’t seem to give them money. Do I trade their diplomatic capital for my gold? What if they don’t have diplomatic capitol?

I know you can ally with some and then kill the rest, but I am focused on how to ally with someone.

Just a little clarification.