4) Learn from your mistakes
One of the best things about social media marketing is that you get your results in real-time - it is not like you post in some sort of black hole and never learn what works and what does not.
That is what makes it so much more effective than traditional forms of marketing. For better or for worse, you will see when your content and strategy has failed, and you can learn from it. There will be some content that does better than others, and some things will fail - but that is totally natural!