Conquering a neighbor civ early.. what would be a typical build order? Also stacks?

[MBison]

What techs would you want to go for as well as what unit types?

Also, I keep reading peopel saying there's ways to do this, but can you attack an enemy unit as a group? Like when I attack a group of enemy archers, my tile stacked with 5 separate unit just attacks one at a time. Possible to attack all at once?

 

[Khaim]

No, you have to attack one at a time. You can still swarm them, though; I just took out a longbow and skirmisher fortified in a city on a hill by throwing five or six units at them and following with my City Raider II Macemen.

Also, Aztecs have a disadvantage with their UU. He's a full point weaker than the unit he replaces, and that hurts. Jungle defense is near useless.