And steal your neighbors workers, then pillage their lands, and come back after they are crippled and take their cities for an early boost.
also..
chop their trees while they arn`t looking
pillage roads that are not within their borders.
interfere with their wars using your units to block them, and turn the war in favor of the civ you like better while still being friends with both
If someone is running away, find a way to kill them, or atleast cripple them.
If a civ has wonders you want, take them.
Learn to love having 0 gpt or less, work on a cash now system. It works faster.. speed is everything.
get a faith, spread your filth.
Wh00re luxuries, and be stingy with them, cripples the AI`s expansion plans.(especially in BNW)
the AI are not your friends, they are your enemies, and you should be plotting against them from the time you find them. Including stealing choice city spots, eating the diplo hit, and making cities you KNOW will be attacked, fortifying them and using them to level your units. (Abusing city states is lame, if you do that go back to cheiftan)
Expect to die, alot, till you figure out how to counter the AI`s massive bonuses. Atilla, Azrects and Zulu will show you the true meaning of Pain.