Ok, I was playing around with the diplomatic options, and I noticed something. If you can trade gold per turn with a Civ, you can say i gold per turn(gpt) for 1 gpt, or an amount that's equal, and though it gives them nothing, they'll say yes. Ok. Put that amount on the trading board again, but don't say "Will you accept?" Instead ask, "What would make this deal work?" They will respond by doing nothing to the offer and ask if it's ok. Now, right click on their amount, and it will say how much gpt do you want? Put it up as high as possible. It still says on the diplomatic options "Accept so-and-so's offer," like when he said 1 gpt for 1 gpt would work. You can keep taking a guys money like this, and he'll always acccept. It also works for resources. Do the same, let him show you a resource and ask what he'd want for it. Then right click the money on your side and change it to 1 gpt. He'll accept. IK this is a bit complicated, but when I was stealing 8 gpt from all 8 other leaders, I was getting 100+ gpt in the medieval ages on 100% research.