In Civ3, the AI loves to build settlers and fill almost all the available territory.
I think you should do this too (have one or two cities with surplus food just churning out settlers).
The type of game you get on a single landmass (pangea) is very different from continents and then archipelagoes.
E.g. Expansionist tribes rely on discovering barbarian huts early with their scout unit (since these tribes never get attacked when entering the huts). But this is most worthwhile on a pangea.
Similarly, if you enjoy negotiation (or early battles), a pangea means you meet the other tribes quickly.
I think you should try to keep up with scientific advances (by setting your budget to as much research as possible; swapping with neighbours; building research building, including Wonders).
Note the many ways to win. I have had much success with a Babylonian cultural victory (half-price Temples + Libraries), but you can also build the spaceship or be elected Secretary-General. Military conquest is possible, but not the only way to win!
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