A good guide to earning gold in wow is by earning reputation. A player's reputation - like a Dwarf's stomach - grows over time with reputation points that are awarded as players complete various quests and challenges for the many factions that inhabit the World of Warcraft and WOTLK. By gaining reputation, a player is able to gain access to many epic items that only faction-specific quarter masters have access to. To gain access to epic items, players normally have attain at least a level of Revered or Exalted.
Players can check their reputation status with a faction at any time by inspecting their character stats. Many players, when they first start out, are usually blissfully unaware that they are earning reputation, but it helps to know your standing with any particular faction as it can come in useful throughout the game - especially when ot comes to making gold.
So how can reputation make you gold?
The many items that faction specific quarter masters sell are usually only BoP and so can't be resold for profit. However, the many patterns, recipes and enchants that are sold will allow players to craft more desirable items or enchants and these can be sold for much profit.
Some factions also sell pets. Many are BoP, but some are not making these factions much sought after by players wishing to attain them. This usually means grinding out daily reputation quests until they reach Revered or Exalted.
Grinding reputation can be really boring with some factions. I ground away for hours with the Argent Dawn until I realized that I could buy 'reputational items' from the auction house and hand these in to the Argent Dawn in return for reputation points. Hence, reputational items will always sell well for sought after factions on the Auction House.
For more information on the secrets of making gold via reputation, follow the links below where all will be revealed.