Update 12/11/13: I am back to working on Strategy Guides for the DLCs. Here are the latest::
Zulu, England, Assyria, The Maya, Wonders, Religion, Civilizations, and a City Strategy Guide
Civilization 5 Victory Strategy Guides
How to Win a Game in Vanilla, G&K, and Brave New World
This Guide was written for gameplay features introduced in both the Brave New World and Gods and Kings DLC. Civilization 5 offers you five different ways to win the game, and these have changed a bit as the game's expansions have been released. This Guide will show you how to win at the four primary victory types (Culture, Diplomacy, Domination, and Science), the fifth being survival until the year 2050, Time, which feels like a hollow victory, a failure to win at one of the actual goals. Civ is a game with many viable strategies, and players can usually switch up their tactics to pursue an easier victory based on the tiles they have worked, opposing Civs around them and how the game is going. Your original goal may not work out. Always keep your options open! Knowledge of all the ways to win will help you switch up your strategy should you find another Civ is about to take the victory and end your game. These guides offer tips on the mechanics of victories, Wonders you may want to build, and should give you ideas that will help you win your next game and up that difficulty level for a greater challenge when your late-game tactics and early-game build and technology orders have improved.
Cultural Victory in Civ 5
The Culture Victory Guide teaches you the applications of Culture and Tourism. Cultural wins require your mid-to-late game Tourism generation to surpass all competing Civs' individual Culture output over the years. Learn the best Wonders, Ideologies, and how to use Great Artists, Writers, and Musicians to spread your Civilization's Influence around the World.
Diplomatic Victory in Civ 5
To earn a win through Diplomacy, Civilizations must first develop a World Congress by inventing the Printing Press, which then evolves as Civs advance to new Eras. In each new Era, delegate bonuses change per Civ, Host, and City-State. Learn about getting Delegates and how you can win the Election for World Leader once the United Nations has been founded in the Atomic Era.
Domination Victory in Civ 5
Brave New World toughens the Domination Victory requirement and makes it much more challenging. It doesn't require outright Warmongering, but is perhaps best suited to that playstyle. In order to win a game this way, you must capture and hold the Capital Cities of all other Civs in the game. Learn some tips on preparing your units for war and how you can take over the world by dominating every Civ on the planet.
Scientific Victory in Civ 5
Scientific Victories are quite popular, probably because people enjoy trying to outpace their opponents in Technology. To win a Civ 5 match like this, build the Apollo Program then begin construction of a great Space Ship to colonize Alpha Centauri and spread your Civilization to the stars. Learn about boosting Science output and production to build your ship together faster and blow past your opponents through Technological Superiority.
A game of Civ 5 lasts until the year 2050, or 500 Turns on a Standard game. A Time Victory merely means that your Civilization survived to the end of the game, and perhaps outlasted other leaders. This Victory is least satisfying, although completing it on a high difficulty is still a challenge. While with other types you may try to win the game earlier, with Time you are judged based on a variety of scoring factors and that is all. Controlling many Wonders, completing Research up to Future Tech and having a high population should all be heavily considered if you want to set a new high score for yourself.