The Terms of Service, the large unavoidable wall of text every player just skips through (and agrees to!) is very important for making gold if you don't want to have your account taken away. While it would be unrealistic to expect players to read through it in its entirety, it is highly recommended. In lieu of that, however, here are some important things you should avoid in your quest to make gold if you value your account.
Chances are if you are reading this book you have already decided this is not an option, but it warrants a discussion either way. Gold-buying is the process of paying real currency for in-game gold and is against the Terms of Service and possibly illegal in some areas as the gold is Blizzard's property and is not for sale.
While many players buy gold with impunity and never get caught, there are consequences if you do get caught, ranging from the less severe removal of gold and items to the much more severe action of your account being banned. This also undermines the legitimate World of Warcraft economy and hinders your legitimate attempts to make gold. Besides, isn't making the gold yourself much more fulfilling?
Botting is the act of using third-party software, or bots, to perform in-game tasks for you and is against the Terms of Service. These pieces of software are usually used to automate tedious parts of the game that are sometimes required but not necessarily enjoyable. One of the more common uses is to "farm" or gather large amounts of base materials, such as ores, herbs, and leather, used by professions.
Unfortunately, it's nearly impossible to avoid dealing with people who bot and with the goods they produce since they don't look any different from the average player and the materials they produce aren't marked in any way to indicate they are contraband. The best route to go here is to avoid dealing with players who openly admit to using bots and to stick to buying off the Auction House if you're unsure, as the Auction House is generally considered by Blizzard to be safe.
If you are unsure whether or not an add-on or software is against the Terms of Service, there is a checklist you can run through. If the software or add-on does any of the following, it is against the Terms of Service:
The software or add-on generates events in the game without the player having to do anything
The software or add-on generates more than one hardware event in the game (per instance of the game running) for every hardware event the user generates
The reason for this checklist is that there is software that allows players to multibox—this clones hardware events to each copy of the game you have running, but only in a 1:1 ratio, and that is the key.
From time to time, changes in the game's code allow for less-than-scrupulous characters to trick the game into giving them extra items. As with the previously mentioned activities, this too is against the ToS and can get you banned if you participate in it. If you knowingly buy duped items, you can have the items taken away from you without any refund of your hard-earned gold. The rule of thumb here is: if it's too good to be true (say a sudden spike in the supply of a super rare mount at rock-bottom prices), it most likely is; so proceed with caution.
There are certain in-game activities that may seem innocent enough but are against the Terms of Serivce. These include but aren't limited to:
Lotteries
Casinos
Selling arena rankings
Selling character levelling
Basically, if it isn't covered in this book, it's likely that either it's against the Terms of Service or the method just plain doesn't work.