Grinding for gold in World of Warcraft is pretty common - you simply do not acquire enough gold in the game as you progress in levels. There is a right way and a wrong way to grind for gold, and 90% of the gold grinders do it the wrong way:

• They wander around too much and never focus on one specific item.
• They don't know how to maximize their gold earned per hour.
• They don't take breaks and get burned out.