The first mistake is using your main character for wow gold farming. This has got to be the most common World of Warcraft Auction House mistake. You say you've got to be kidding, after all this is the way 95% of the gamers play the game. While this technique works we'll grant you that it makes the game boring, real fast. Why? Simply because it changes the way you play. All of a sudden the game becomes more about your World of Warcraft Auction House alt, then your main character. Your game has now changed in that, it no longer is about raids, endgame instances or battlegrounds it has become all about this lowbie auction alt. You become fixated over the idea of gold farming, and the next thing you know the game becomes repetitious, you get bored, and you stop enjoying the game.
   The second mistake is posting too many lots of the same item at once. When your sitting on 10 different stacks of Fel Lotus, you gain nothing by posting it all up at the same time. We won't even consider the chance that some of your items won't sell costing you re-listing fees, that would be too easy to point out. Instead what you're doing wow gold is de-evaluating the item. Others start under bidding you, and the next thing you know, you've dropped the market price, your items didn't sell, and now you have to re-sell for less. Instead be patient, if your sitting on tons of inventory, stick to selling only 3-4 of the same item each time.
   The last mistake is buying blues and greens for resale. We know that you may think this is the backbone to playing the World of Warcraft Auction House. Again this is another very common mistake most people make. Here, again you risk not being able to turn the item around for a profit, which in the end will cost you more then the item was probably worth. This is especially true of trying to sell Outland Green items. We can say that you have tried and noticed that it could take upwards of a week or 2 sell one some of these, and it probably cost you several gold just to do so. Unless it's a twink item you'll make a lot more world of warcraft gold staying away from re-selling blues and greens.
   As above mentioned, these are the three mistakes most gamers make in the game to amass lots of cheap wow gold. So by now you should take more notice and avoid doing these mistakes again. Good Luck!