I realize this depends on the leader you're playing as, your map, your opponents, and your victory goal, but to the extent that you can generalize, what are some good milestone goals to shoot for when playing on higher difficulties, say, Emperor and up. For example, get your first setler by x turn, get Political Philosophy by Y turn, etc. What should I be aiming for if I'm shooting for a domination victory on a leader that doesnt' shake things up much?