How to get followers on google plus business page? Keep in mind that you don't just want to grow your numbers. You want engaged followers. Here are 5 Best practice for getting google plus followers to increase business credibility.

1. Don’t be afraid to +1

The +1 button is very similar to the like button from Facebook. The biggest difference pertaining to this button is you don’t +1 a business page on Google+, you instead add it to circles just as you would a personal profile. When you +1 someone’s posts or comments it shows your appreciation and your personal seal of approval. Many websites and blogs are including a +1 button with their content allowing you to tell Google that you’ve found important or relevant information. With recent changes to Google search, content you’ve +1’d show up in your friend's search results. How does this help you increase Google+ followers? It’s simple, you’ve just earned some gratitude. Your +1 essentially helped the original author with social media marketing and SEO at the same time, with one click. Not all Google+ members realize this, but the ones that do will be happy to add you to their circles in appreciation.
Also read: 5 Reasons to Use Google+ Hangouts on Blog

2. Add a Badge to your website or blog

It is really easy to add a Google+ badge to a website or blog and increase reach. you can use this simple tool from Google to create icons and badges of different sizes. These badges will allow a quick and easy way for followers to find your page, similar to the Facebook boxes most people use. It is also just a great reminder for visitors to find ways to interact with websites and people they enjoy.

3. Engage with industry colleagues

Online marketers should already be familiar with this concept and use it often on Twitter and LinkedIn. One of the most effective ways to increase your follows is by participating in the discussions of others. Find the profiles and pages of those that are relevant to your industry and provide encouragement, helpful comments, and suggestions. Just like on other social networks, this practice helps establish yourself as an expert and go-to person.

4. Ask on other social networks

If your goal is to move some of your conversations to Google+, this may be a very helpful task. Some of the reasons you may want to migrate current followers over to Google+ is to take advantage of features like hangouts and social Google search results. If you have a large Facebook or Twitter following, it can’t hurt to post a link to your Google+ profile or page with a quick note to follow you over there. A beneficial side effect of doing this is increased engagement from followers that prefer Google+.
Also read: How to Create and Setup a Google+ Page for Your Blog

5. Add links to Newsletters or email correspondence

Many of the newsletters that I receive from my favorite websites include buttons to follow on Facebook and Twitter, why not add Google+ to this? Like almost every professional in the world, we all send and receive many emails. In the signature of your emails, it might be a good idea to add links to your social accounts in addition to normal contact information. 
You can make your own links or use the Google badge creator from #2.