The key to a good social-media campaign is to know why you're running the campaign in the first place, says Mitch Joel, president of the marketing agency Twist Image. Only then can you begin to figure out how to actually achieve your goals, he argues. "There's a big difference between asking 'what?' and asking 'why?'" he says. "Asking 'why?' is the strategy and asking 'what?' is the tactic, so it's all about figuring out the 'why?' first."