Step1
Make a new Character on the same server as your Main.
*Alliance: Consider Human or Night Elf because their capitols have less lag than Iron Forge, typically.
Great mule classes include Priests, Druids, Rogues, Shamans, and Paladins for their survivability. Plus, healers seem to automatically be on everyone's good side.
*Horde: The Undercity is not usually as laggy as IF, so Undead is a good choice, for their close proximity. Of course, if you want to be beautiful, you can roll a Blood Elf.
Step2
Take your Main to about lvl 10 or so (if you occasionally want to move your mule to a new location, you wouldn't want a constantly-dying lvl 1 mule) and then plant them in the capitol of your choice. My favorites are Stormwind and The Undercity.
Step3
Log onto your main and begin grinding, questing, and looting to your heart's content.
Step4
When you are out of room for more loot, skip to the nearest town and
*Sell all grey items to the local vendors
Then
*Mail all other items to your mule! Remember that your mule doesn't need to receive all the items at once.
Step6
Log into your Mule at least once per day to:
*Scan the market with the WoW Auctioneer add-on (read more on that at http://wowauctioneer.wordpress.com) to get the latest pricing information
*Receive the mail from your Main
*Auction the items in the Auction House that will sell for a profit
*Enchant or Dis-enchant items as needed (sometimes this makes the difference in the AH between a profitable and non-profitable item)
*Store important items in the bank
*Sell of the trash to vendors
*Send money and important items back to your main (great way to get food, drink, new equipment, and money!)
