If you’re making a new character on an established server, one quick way to make gold is selling pets on the auction house. The most money can be made by selling/buying pets across factions, but you can make a fair amount of gold just buying pets near your local capital and putting them up on your own auction house. You won’t get rich, but you can make a solid amount of money.
EDIT: Greedy Goblin has more on making gold on a new server.