How to gain the Reputations Easily?

After the first chapter about the Wotlk factions introduction and the things you should know before you get 80, this chapter is about the 4 regular factions.

Argent Crusade, Kirin Tor, Knights of the Ebon Blade and The Wyrmrest Accord
As the picture below, four new head enchantments are the most important faction rewards because they are not replaceable throughout Wotlk. You can find some gears those are helpful for you, but you should know what is the first. Ok, buy a tabard and begin your heroic dungeon adventures.
Tabard of Kirin torIn fact, it would be better to say “how to run heroic dungeons quickly” rather than “how to gain the reputations of these 4 factions easily”. Once you reach friendly with these factions, the best way to get exalted is endless heroic runs. So, I have some suggestions for you about which heroic dungeons are the easiest ones in wotlk for you if you just get 80 for a few days.Utgarde Keep in the center of Howling Hjord is the best choice no matter what you want, the reputations or the badges, there are 3 bosses here and easy to defeat. Nexus is another good choice, additional melee boss(like Watchkeeper Gargolmar in Hellfire Ramparts) had been added in the half way of frozen gauntlet compared to normal difficulty so it has 5 badges in total. If you can find a good tank, you can try Drak’Tharon Keep southwest of Zul’drak and The Culling of Stratholme in the Cavern of Time. Both of them are short runs and have nice loots and badges.
wanna read the details, plz check http://blog.swagvault.com/2008/12/16/how-to-gain-the-reputations-easily/