sometimes hard to work out what sort of behaviour and practices are acceptable ingame, and the "grey area" of
slightly dubious practices is filled with dodgy dealings that some players applaud and others despise. One of these is
auctioneering--the well-established practice of playing the auction houses to maximise one's profit.
One of the most common tricks players use is to have an alt sitting in the AH, and to mail goods for sale to that character. You can then log on as that character--also called a mule--and do your AH trading without the bother of having to transport your main character to and from the auction house. More advanced strategies involve the use of tradeskills along with the mule, such as learning Enchanting so that you can disenchant any rare items: enchanting components often sell for more than the original item. You can also give your main character gathering skills (mining, herbalism or skinning) and your mule corresponding crafting skills (blacksmithing, alchemy or leatherworking), even setting up strings of mules for the most efficient use of your loot.