There are many ways to make huge profits in World of Warcraft. Unfortunately time doesn't allow me to put them all in this report. However, here are three of the best ways to make gold profits if farming gold in Cataclysm.
1. Vanity pets. This method is a long shot. Farming a vanity pet can be very rewarding or just a waste of time if you don't have that certain dose of luck. You can get one in minutes and sell it for 1000's of gold, or waste a couple of hours only to end up with one or two bags of useless junk. Anyway, if you do get the vanity pet you've been farming for, your investment is only time. Therefore, all the gold you're going to get for it is pure profit.
2. Crafting wisely. If you have at least a crafting profession on your character, you have to know that there are recipes out there which not many players have, or recipes for items that no one crafts anymore. Example, Formula: Enchant Weapon - Spellpower. Of course, for this item enchantment the materials are a bit expensive, but there items that can be crafted and sold for 1-2000g and all the materials are very cheap. So, to craft wisely, means to buy materials for cheap prices, use them to craft an item which sells for 3-4 times the price of the materials.
3. Auction House trading. This is the ultimate method of farming gold in Cataclysm. Every pro player makes their money this way. It's a very profitable method, but it's risky too. So, to be successful you need some training. Since it takes time to learn all the secrets of the Auction House and use them to your own profit, it's best to work with a WoW gold guide. I had to burn myself a few times after I lost a few thousand gold by investing in the wrong stuff to realize that. Anyway, the guide I've been working with has instructed me exactly how to conduct an elaborate research on the Auction House on my server, make only profitable investments, minimize the risks and maximize the profits.
Therefore, if you want to make huge profits farming gold in Cataclysm, the best teacher I can recommend you to start with is a WoW gold guide. I'm saying this because this way I managed to get the 40k I needed for my Vial of Sands in just one week.