There seems to be a parallel to life here - since my character hit 32, she's been working diligently at improving her financial state in the game. With the goal of the "mount" at level 40 - the animal I'll be able to buy and ride around the game (faster) instead of running places on foot (slower) - comes the goal of amassing 100 gold coins so I can pay for the riding skill (20g) and buy the mount itself (80g).
I really should have been writing during this period, writing the discoveries, etc, but... I've been working on gathering the money, and not on writing ;)
I'm proud to say that I'm now lvl 38 and I've got 107g, so as soon as I hit 40 I'll be able to get my mount, and I should have extra money left over for training as well.
And hey, I earned all that cash by MYSELF! I didn't buy any WoW Gold from any of those websites or anything. I worked a lot on leatherworking (I'm at 212 now) and am close to maxing my Skinning skill at 300, and sold a lot of leather items through the Auction House. I found that Dark Leather Tunics and Dark Leather Pants sold reliably and for 60-75s each, so especially while I was getting Leatherworking experience for creating those things, I created a bunch and sold them all.
A second thing I did was run through instances that are low-level compared to me. I went through WC and RFK and picked up a bunch of Uncommon items that sold quickly in the Auction House.
The main source of my cash, however, has come from travelling to other towns and cities around the continents and buying limited-sell recipes and patterns then reselling them for 4-5x their vendor price in the AH.
Every time I logged in - especially in the morning when the player count was nice and low - I would fly around on the wyvern and visit different Horde towns I had flight points for, buy their limited-sell items, then eventually return to Thunder Bluff and put them all into Auctions.
I have a WoW User Interface Addon/mod that helps me determine which of the limited-sell things have a history of selling well in the AH, and from there I've learned from experience which patterns and recipes are sought after and which don't tend to sell as well as hoped.
I'm not going to tell you which patterns and recipes have done well for me, I think I've given enough information to introduce significant competition if there's anyone who lives in the same realm as me!