My gold making venture in Cataclysm has been a great success so far. I've earned more than 70000g from simply selling stockpiled Glyphs, and still got a few bags left. I earned several thousand from nothing but Small Egg sold at prices ranging from 5g to 25g, which I farmed several hundred of in less than an hour in the old Darkshore. I also earned close to 10000g from selling all the Enchanting mats I acquired while leveling. I was in no hurry to level my professions, and Hypnotic Dust sold for 500g - 600g each stack. Waste not, want not. Sell when it's expensive, buy when it's cheap. Simple rules that always guarantee a profit.
Today I have two very small tips to share with you. Both of them requires Enchanting, and one of them also requires Jewelcrafting. The first tip has been posted on pretty much every gold blog there is, but a good thing can't be mentioned too often, can it?
First, get your Jewelcrafting to 460 if you haven't done it already (and I'm assuming you were at 450 when Cataclysm launched...). This is extremely easy, and can be done with roughly 15 of any random collection of the new Cataclysm green quality gems. Now that you're 460, it's all about crafting Carnelian Spikes! They cost roughly 60g - 70g to make each, and assuming that your server is anything like mine, the profit from disenchanting and selling would be close to 100g per item. And if you sell scrolls of enchants wisely, you can make more. But that is not something I'll go into detail on here.
The second tip only makes a very small amount of gold, but everything counts, right? First off, you do as mentioned need Enchanting, and secondly you have to be a Druid, Shaman, Death Knight or Paladin. Why? You need to be able to buy PvP Relics.
I personally buy a Bloodthirsty Gladiator's Relic of Dominance for 700 Honor everytime I hit 4000 Honor. Any Relic you don't use is ok, as long as you can pick it up and disenchant it. I choose a Relic over any of the other items simply because they're the cheapest items available from the PvP vendor, and they all shard to the same single Heavenly Shard. Not exactly impressive profit here, but that Honor would have been wasted otherwise. And every little copper helps!
For reference, on my server the average prices for the relevant items at the Auction House are:
Hypnotic Dust 10g
Lesser Celestial Essence 20g
Greater Celestial Essence 60g
Heavenly Shard 80g