The most common and often important metrics to pay attention to are engagement, impressions and reach, share of voice, referrals and conversions and response rate and time. These combined will give you a 360º view of your social media performance. With time and new goals, you’ll add new and more nuanced metrics to make them more relevant to your business.
Your social media goals are what determine your metrics. For every goal, you need a related metric, which will help determine if your social strategy is hitting the mark or not.