In addition to strengthening your overall social media marketing position, it's going to be absolutely critical that you are investing in your Google+ presence.

Moz's most recent study of ranking factors confirms that Google+ is playing an increasingly significant role in a solid SEO ranking. The immediate areas to focus on include:

Establishing Google Authorship of your content, and tying it to your Google+ account. Authorship, which brings your body of content together, will play an important role in the SERPs as well as strengthening your Author Rank.
Those +1's add up. It isn't clear exactly how much Google +1's directly contribute, but it's fair to say that it's a major factor in the "social signals" component of Google's algorithm.