Question
The company sells online courses for a variety of topics in the holistic / "new age" sector including: personal development, spiritual growth, conscious business practices, etc.
Their email opt-ins are for free teleseminars or telesummits, or "preview calls" for their paid courses.
They already have lots of free content -- mostly text or audio -- that they could share.
They already have a sizeable email list but they don't want to distract their email subscribers, so the new Google+ presence can be mentioned but not actively promoted there.
Again, the main goal is generating email opt-ins for their free teleclasses.
keywords: social media, google plus
Answer
The simplest method of growing this would be to ensure you are putting out relevant content showcasing your company across the largest applicable groups not only on G+ but also sharing the content you post on G+ to prominent groups across LinkedIn and Twitter as well. By combining the business focus of those 3 networks in tandem with solid content your corporation can quickly become well established in the first 3 months.