Trade with civs often. It doesn't matter if you buy from them, or they buy from you, but be generous in these trades. If you could sell the English a luxury for 10 gold/turn, sell it to them for 5 gold/turn instead. In wars, they usually are polite if you are an ally. They will be Gracious if they had previous problems with the mutual enemy civ and/or you do most of the damage. I used to let other civs do most of the fighting and almost never had anyone gracious, then I started doing most of the fighting by capturing cities and would get some of my allies as Gracious. Don't ever Raze a city, though! If you capture some useless city that's way too far from your capital and it was formerly owned by another civ, give it back to them as a gift.