Looked at the 760 AD Cleo game. VMXA has covered a lot of good detail, so I'm just going to reiterate the high level concepts you should be aware of:
1) 1 worker per city, do not automate, irrigate plains and mine grasslands
2) Put the cities a little closer together
3) Don't waste your shields on wonders. Maybe 1 or two key wonders. With the rest build things you can use. The AI can build the wonders for you.
4) Explore so you can meet the AI. By 760 AD you should have a good idea of the map.
5) When you make war, get alliances. It will cut down the amount of units you have to take on.
I spend in wonders becouse, if i continua spending in military the upkeep killme and the same for buildings