A strategy that I use, almost every game, is what I call the "axe squat".
I play on Diety, huge, marathon maps, 18 AI's, aggressive AI.
The "axe squat" consists of researching bronze working first and building about 3 axes as quick as possible. I then use these axes to find 2 neighboring civs and scout their borders. Once I find a worker unprotected on the border, I will steel the worker. Then I use the axe to pillage all of their land. After the AI has been pillaged, I will squat the axe on fortify on a wooded/hilled tile right next to their two cities.
This will cause the AI to do nothing but produce archers. This will keep the AI in a state of non-advancement, and give me a huge land advantage with lots of space to grow.
Sometimes I almost feel like it is taking advantage of the AI's stupidity, and feels kinda like cheating. But its not, so.... Yea - that's the "axe squat"
Try it out on your next game. The advantage is decreased neighboring threat, and room to grow unhindered. But the disadvantage is decreased AI attitude, and a more overall aggressive position toward you from other AIs.