First you need to understand what your company/ organization stands for: key messages and positioning.
Next, really be targeted in who your customers are: demographics, psychographics and last of all of course socio graphics! Which social platforms do they go on? What do they do on there?
From there you can craft a social media marketing plan to engage with the right content at the right time. With engagement, then you can build up to a call to action, which could be signing up for a newsletter etc., eventually buying your product or service.