Ten tips for those who could not be bothered to read the manual:
Geography:
1)
Know what land is worth: Build your cities on good land.
Aside from your starting resources, every single resource in the game comes from land. Every one.
-Food sustains and produces citizens, which help you gather more resources. Two food sustains one citizen.
-Commerce sustains cities and military units, and helps you research technology.
-Production lets you build buildings, military units, and special projects.
-Special resources like Wheat or Bronze have special applications. Some give additional happiness to all cities in your empire, some give additional health, some allow access to special military units, and some make buildings cheaper to build. Multiple special resources of the same type are redundant, but may be traded with other empires.
Cities have access to the 21 land tiles around them that are within your empire’s borders (a 5x5 box with the corners trimmed, a “fat cross”

. Know what land tiles produce what and know what they're capable of producing if you invest in them.
2)
Scout: Measure twice, cut once.
As important as it is to build your cities on good land, it’s just as important to know where the good land is (and where your rivals will be coming from).
Your first few cities will probably be close to your capital, but the earlier you get a sense of your surroundings, the more informed you can be when you plan your empire out.
3)
Grow: Expand intelligently.
The earlier you claim land, the less you’ll have to fight for it later. But if you expand recklessly, you may be spread too thin to support your empire militarily, socially, or economically.
The core of the game is accruing enough power to win. The meat of the game is striking a happy balance between growth and strength.
War:
4)
Defend: Trust your rivals as far as you can throw them.
Never send out settlers without a military escort and never leave cities undefended. It is extremely rare to go an entire game without crossing swords with somebody and the weaker your defenses, the more likely it is that rivals or barbarians will invade.
5)
Attack: Take what’s rightfully yours.
At some point, there will be no unsettled land left to claim. If you wish to expand then, you will have to start claiming settled land.
Bear in mind that advantages don’t last too long in Civilization. It’s best to press them when you have the opportunity.
Peace:
6)
Make friends: Trade to get ahead (well technically, to get even).
You can’t fight everybody all of the time. There are generally 5-12 Civilizations in any given game and making friends with some of them is important. A friendly civilization will be more willing to trade technologies or make alliances. Access to their resources was what you wanted in the first place; with diplomacy, you can get it without a costly and unnecessary war.
The combined might of your two empires can give you a good leg up on the other dozen civilizations. And you can always turn on them later if you have to.
7)
Be first: Beat rivals.
The first Civilization to settle on land gets to keep it. The first Civilization to research a technology gets the bonus or founds the religion and gets to trade it away before anyone else can. The first Civilization to complete a Wonder of the World is the only civilization to complete it.
As with war, you must press your advantages in peace, if not more so. While war makes your empire grow, peace makes your empire strong. Engaging in a war while running a race may hinder progress towards a peaceful objective that’s often more important than screwing your nearest neighbor. There’s your next-nearest neighbor to think about.
Technology:
8)
Know what you need: Direct your research.
Not all technologies are equally useful. Bronze working reveals copper, lets you build Axemen, lets you use slavery, and lets you cut down trees, being useful for almost every single game. Sailing is obviously pretty useless if you’re not near water. Drama is similarly often useless without dyes or happiness problems.
Don’t concern yourself too much with researching every tech. If you don’t really have a pressing need for it, there’s a good chance that you can trade for it for cheap later on.
History:
9)
Have a plan: Set goals.
Success in Civilization is staggered.
10)
Don’t get emotional: Think strategically.
The AI is programmed to be emotional. You don’t have to be.
On the other hand, it’s a game; play as emotionally as you like! *_* Found all seven religions in the same city! Drop 20 nukes on France! We’ve all done it; you know you want to.