Try hunting a variety of things which you can handle and auction everything you come across that you don't need. Pay particular attention to how much you make vs. how quickly things sell and sooner or later you'll pick up on which items are the most profitable for you. Best way to do this is to research the AH's price history on items that are easily acquired for you, then go hunt those mobs. There's also always Gobs and Orcs, they drop money as well as items. It may not be much money, but it helps.