There are so many different guides that all lay claim to teach you how to make gold in World of Warcraft and each of them has a completely different take on the subject. After years of play it seems like there are several ways to go about making gold, based on your character and of course your chosen professions. One thing that seems to remain a constant is that raw materials always command decent prices in the Auction House and with an expansion out these raw materials are in high demand.
The secret to making gold in World of Warcraft lies in using both your professions and the Auction House wisely. One of the best ways I have seen to make gold quickly is to have one toon that is both an herbalist and a miner. Once you have access to the top ores and herbs, you will find that one or two hours of farming can be turned into hundreds of gold selling them in the AH. With so many players trying to level their professions, the ores and herbs are commanding ridiculous prices and are likely to stay that way for a while.
Wait, you say that prices aren’t that good in your AH because there is plenty of Titanium or Frost Lotus. This is the time to put your best Auction House strategy to work for you and buy out everything at lower prices and then relist some of it at the price you want to sell it for. When there is nothing in there but what you have for sale, players are going to pay your prices. This is a rinse and repeat operation and will hold the prices up where you can maximize your income.
During the early stages of any expansion the stuff you have been crafting and selling is not going to sell very well as everyone is more interested in levelling both their characters and their professions. This is the time to take advantage of the situation. Farm for all the herbs and ore you can and sell it all in the Auction House, you can worry about leveling you other professions later as the demand and the price of the materials starts to go down.
While these are not the only ways to make gold in World of Warcraft, they have proven to be very effective in each of the expansions and are continuing to do so at the moment. Take advantage of the early days and you will make more gold than you know what to do with.