Actually, nothing really complex Built cities on 1 tile distance (smallpox). Invaded America ASAP but didn't stayed just there for a long time. Bought trireme and chariots in London and invaded Europe. Captured all of the Russian cities exept for Moscow (damn walls). Then had a long war with Zulus.
I can give everybody here some advises for beating such a challenge:
1) Smallpox is the best strategy ever.
I've never heard of the smallpox strategy. But now that you mention it I have to give it a try.
Especially since I don't like my cities being bigger than 3-4. So I can just have a temple and phalanx and churn out chariots.