Let me be frank.
While social signals play an important role in Google's algorithm, they still take a backseat to quality links and content.
However, if you're confident you have those 2 elements sufficiently nailed down for the time being, it makes sense to start tackling other ranking factors like social signals to help push rankings.
I like to approach my social signals recipe the same way I do link building, with a sprinkling of diversity.
Roughly 40%-60% of your social signals will come from "the big three": Facebook, Twitter, and Google+.
And roughly 40%-60% of your social signals will come from a basket of social sites such as: