Since I pretty much said everything about how I make gold in wow, I thought I should also mention some markets that not everyone is in, but might be profitable.
First of all, vanilla enchants! In case you haven't noticed, people make alts and, usually, they want to level them as fast as possible. This is why allot of them use heirlooms and also enchant them with the best possible enchant available. This is where you come in. Get some old world reputations up, buy some nice enchants for shoulders, chests and weapons and start selling them. The profit margin on these things is usually huge and there is very little competition. Some of these would be the +15 Agility on weapons, anything that increases Intellect or Spellpower, basically anything that would give a big boost in damage or uptime for low level characters. There are also some non-heirloom enchants that you should be looking at, like the Healing Power one for bracers.
As for other professions, Leatherworking, Blacksmithing, Tailoring and Jewelcrafting should all be able to make some decent money on selling Northrend blue items, especially tanking sets and stuff like that. These are a bit harder to automate, but it's still doable, you just have to make more item groups in QA3.
Tailoring should be pretty decent with Netherweave bags, but only if you have a cheap supply of cloth.
Engineering I have no experience with, but I seem to remember buying some engineering items on the AH for various quests, so you should look into those. Scopes and Ammo will sell well to, probably.
For Blacksmithing, be sure to see if those Enchanting rods are profitable. Other than that, you will probably be limited to Northrend stuff.
I'll try to think of some other stuff, but, as I said, I don't have much experience with some professions so I can only do so much. In any case, I hope this will help.