Tips and Tricks
America and China are two of the most powerful in the game.
No matter if you play an aggressive or a defensive game you need a solid defense because you’ll be declared war upon a lot.
Make sure you have walls and archers early on to defendi your cities, and few offensive units to destroy the enemy if need be.
Do not trust your neighbouring civilization.
Placeing a warrior on a hight point, hills or mountains nearby, will get you scout and you'll “see” better what troops are incoming and you can prepare to greet them.
When your civilization become very large it's far better to only defend the borders than individual cities. A solid defense and offense stacked around your border so that the cities can be kept very light on troops.
Try to be the first to get access to the Galleon (or the Lighthouse of Alexandria) so that you can explore the ocean. The goal is to be the first to discover Atlantis for the tech boost.
Plan your science development because getting all the techs in order is not the best idea.
Expand quickly if you want to make sure that you get a great spot and no other civilization take it. The sooner you build your second city, the easier for you to progress faster.