The single most important thing in World of Warcraft is to be able to have a lot of gold. The more gold you gave the more items you will be able to acquire one of the most important aspects of the game. You can also use gold to buy items from vendors but you can sell it for a profit.
Also keep in mind that in World of Warcraft gold can be used for training your character. Even though a lot of gold would be required to perfect your character if you start collecting gold early it will be easier to acquire the gold.
A good idea would be to start a profession as soon as you can. At the same time you will be able to level up your profession and be more experienced. As a result you will enable your character to do more things and be more effective.
Most World of Warcraft guides out there advise that you take on two professions early on. Even though there are many professions for you to choose from the best professions are mining and skinning.
Killing animals and then skinning them will be great way to generate gold in World of Warcraft. It is so, because you can take the skins and then sell them to vendors for a profit. Skinning is great if you want to build up your gold deposits early on in the game. By doing so you will be leveling your profession too.
Mining is another great and popular profession. As you travel you will run into caves that could have precious minerals. Some of these minerals are in high demand and you can collect them and sell them for profit as well.
These are only two ways you can make gold in World of Warcraft. There are other ones as well such as questing. It is all about being creative and persistent. It would not be a bad idea to consult an official World of Warcraft guide to walk you through the best ways to make gold in the game.