Just play like you usually do on chieftain except build less ancient age wonders.
This is a good point. A few others:
1) Build lots of workers. You'll never have enough (
at least 1 per city, hopefully more).
2) Road every tile your cities are working for the commerce bonus.
3) Use the science/luxury slider (don't use entertainers for happiness) on the F1 Domestic Advisor screen.
4) Keep expanding until there's no room, and don't have big gaps between cities (usually 2-3 tiles between is good).
5) You don't need to build every improvement in every city.
6) Trade with the AI (or at least early in the game when they have stuff to trade) to speed up the tech pace.
Also, check out the
War Academy for some good tips. I know this wasn't your question, but
everyone can use advice!
Overall, the change from Chieftain to Warlord results in the AI being less severely penalized.