Having high end tradeskills for a range of trades is another method.

Let's say you have a Blacksmith, Enchanter, Leatherworker, Jewelcrafter, Scribe and Tailor.
Look for the high end recipes, which create the best crafted options available.
Look at the cost of the materials to make.
And what the final product is going for on the AH.

Many of these products will not be profitable to craft.
But you can do free combines and accept tips.

The ones which are profitable, get an idea of the mats you need.
Then have a few macro's made up. Something to the effect of:
/Trade Buying stacks of AAA, BBB and CCC, send to Toon CoD
Have a few spam macro's, which you click every hour or so, or whenever you pass through a densely populated zone.
You don't want to irritate people with the spam.
Price your stacks so they're cheaper then what you'd pay buying them on the AH, but fair enough priced that you're still a decent deal compared to listing stacks 2-3 times before they sell. A lot of mass farmers will CoD to you for a guaranteed sale now, rather then risk the AH.
List your items on the AH, but don't flood the market.

An example of this... One stack of Netherweave is enough cloth to make a Netherweave bag.
Price what a netherweave bag goes for, if you can get a stack of cloth for less then this, you can sew for a profit.

And netherweave bags are consistently one of the best selling items across all servers.
For proof, go to www.worldofwarcraft.com/toplist
Then click on the "Auctions Sold" tab and choose a 7-day view.