The island start is one of the most frustrating starting positions. You are alone, with noone to trade techs with, so you know you are falling behind. You run out of space very quickly. However, it can also be one of the strongest. But only if you play your cards right. Here’s how.
(1) Be realistic. You can’t afford to waste time on Wonders, libraries or anything like this. You have one priority: get off the island!
(2) Remember: you island is also your fortress. Be damn sure you leave no space for a wandering AI to pop a settler on. A few temples for culture is worth the investment.
(3) Try and work out where the nearest land is. Best bet is usually towards the centre of the map. But very often, you will be able to work it out from where the shallow water extends further, or you may even catch a glimpse of a rivals borders as their influence extends. Stand on top of mountains and stare out to sea!
(4) Put as much effort as you can into getting to map-making and your first ship! But build two. You will need to create a conveyor belt, to make sure you military never stop moving.
(5) Once you have map-making, shut down the research and build up cash like crazy.
(6) Start building as many of your strongest units as possible. Ideally swordsmen, which usually beat everything until pikemen appear.
(7) When you finally meet your neighbors, start out nice. Also don’t immediately buy techs. Instead, buy contact with as many AIs as you can, and if you can get their territory maps, so much the better. Talk to them all. Assess who has what techs. Chances are they will all be far ahead of you. But if you buy techs that only one AI has, you can sell it on, and trade it for the others. 9 times out of 10 you can get back up to speed.
(8) Establish a beach-head! You strategy now rests on getting as much military on to your neighbors patch as you can. Pop down a settler on any patch of coast you can grab. Conveyor belt your swordsmen in, until you have at least 10-15 of them there.
(9) Attack! Enjoy!
This strategy has served me well. The key thing is not to get sidetracked into anything other than expanding off your island. This start is hard enough without wasting shields on things you don’t need. Once you achieve this, your island base is a fortress: hard for AIs to attack, and your base for conquest!
As a final aside. When you do make your second home off your island, it will be horribly unproductive. You will have to prop it up from your fortress island. Meanwhile, crawl your way to the Forbidden Palace. It might take a 1000 years to build, but when you get it is well worth it. But if you are lucky enough to get a leader. The FP is what to use him on.