Create Intelligent Circles
Google+ is the one platform that allows you to create different circles based on shared interests. This allows you the ability to tailor your content to the users in your circles. For example, you can create a circle that allows you to promote a certain product or service to users who have an interest in such. Or, you can create circles that deal with certain aspects of your company such as Sales and Service. The idea is that you create different circles that allow you to customize and target the content you post so that you maximize its efficacy.
Join Related Communities
Communities abound on Google+. Joining the ones that interest you will help you find users that you can add to your circles. The main thing to remember about communities, and about social media altogether, is that it's not just about advertising. You need to participate from a personal perspective and keep advertising to a minimum. Engage with community members and make friends. Ideally, community members will begin looking at your profile and visit your company without you ever having to say a word about it.
Link your Content
Get the most mileage out of the content you are posting on your blogs, website, and other social media accounts by linking to it, instead of just randomly hopping around. Google+ thrives on real content rather than passing thoughts and random updates. This means that you need to be prepared to share something more meaningful that what you just had for dinner. Linking to your primary content location will help you do just that without requiring that you write specific content for Google+.
Become Familiar with Hangouts
Google+ hangouts, like communities, are everywhere and are a great way to connect with others. The main difference between communities and hangouts are that you can conduct advertising events such as webinars and hold virtual meet and greets through the hi-res video chat feature in order to help familiarize potential new customers with your company and brand.
+1 Other Posts
Google+ gives you the opportunity to engage with others by using the +1 feature. If you want to grab the attention of a particular user, you can +1 their content, although it's important not to just start +1 ing all the content you see. You have to be consistent and thoughtful with your +1 activity in order for it to have any credibility with users.
The Payoff
While Google+ might still be an up and coming social media platform, it offers a lot of benefits to companies over more traditional social media outlets. It might take you a little bit to learn the ropes and become established, but your efforts will be well rewarded. You will end up with circles of users who are actually interested in what you have to offer and can turn casual visitors into loyal customers.