Check out this link
Its an SG on a huge map, you'll pick up lots of good pointers from these players.
A couple things I'll add:
1. Have a powerful computer unless you like doing something else while playing Civ
2. Tell your wife/girlfriend you'll be working on a project for the next couple of months
3. Plan on surviving on 3-4 hours sleep the rest of the year
4. Enjoy the game
About the game:
1. Build cites, then more cities and then more cities
2. Look for a start on a river with a food bonus (not an FP) for a good 4-turn settler factory
3. Choose America - the expanionist trait for your AA techs and Industrious for faster workers
4. Build at least 4 scouts
5. Have each city build a worker asap, then go to normal builds
6. You won't have a corruption problem for the first couple of ages, so don't bother with courthouses
7. If you pop a hut and get a city, don't disband it if it's in a bad place right away, wait until the city limit has been reached and sacrifice it to get a city in a place you want
8. The limit on cities is 512 keep building them until you reach the limit, then have a extra 1-2 settlers and try to build a new city each turn, in case one of the AI's got razed
9. Start building military with a unit you can upgrade, because you won't be fighting until the late middle ages
10. Choose faster units as you will need them to reach your opponents in under 10 turns
11. Don't plan on a domination or culture type win, they are very tough to get. You might not be able to ever get enough land to reach 67% and getting 2x culture on an AI is tough unless you kill the larger ones
12. Skip research for the AA, let your hut popping get you science, but remember you can't get the tech you are researching, so research an optional tech to allow the huts to get you the middle ages (caveat to this is be sure to get a government tech before leaving the AA as they take a long time to research and are valuable in trades)
13. Expect to be behind in tech in the middle ages to at least a couple of AI as they'll be trading techs around faster than you can
14. Try to keep continents isolated from each other and be the trade broker between them
15. Once the wars break out, make sure you get your other neighbors as allies, cause if you don't your opponents will
16. Encourage wars on the other islands, it gives the AI's something to do with their troops and distracts them from research (and cuts down on tech trading)
17. Try to get a dogpile on your #1 opponent
18. If you find yourself on the bottom of a dogpile, defend against the stronger opponents and attack the weaker ones, Try for peace with the stronger after 4-5 turns, but keep beating on the weak ones until the ask for peace, then get cities as tribute.
19. Until Combustion, ships are only needed for transportation and exploration, so ignore frigates & ironclads
20. In the end game, if going for a military win, expect to need bombardment units (artillery, battleships, bombers & nukes) to take the size 20+ cites the AI will have.
That's a nice little 20 pack, so enjoy, have fun and remember it's only a game...