There are numerous ways to use Google+ to engage with current and prospective customers. You will need to decide how to showcase your brand on Google+ and how much time to devote to this platform.
Things to understand about Google+ before we dive too deep include:
Interacting on Google+ is similar to interacting on Facebook: users post content and it shows up on all followers' walls. Consider the example post below from Pete Cashmore of Mashable.com:
For an alternate view, check out this screen shot from AT&T's profile:
Note that it is very similar to a Facebook company page, with logo, images, followers, and posts.