Be visible on social media networks even when you do not have anything to promote. Just a quick update will do. Speaking of promotion, do not use social media to list down product specs. This is engagement, not an ad.
Make sure you do interact with your followers, and if possible, follow them back. Be cool with comments and do not repel negative ones. Make sure you do have personalized posts and not templated ones. Lastly, remember that communication is a two-way process.
Source: Business 2 Community