Find 5 or so people and/or G+ business pages you like to follow who have lots of G+ users commenting on their posts. Start commenting on those posts, and start circling those people. People will circle back.
I’ve been doing this slowly but surely since joining G+ in July and lately I’ve seen a big increase in circling, and in Google Plus business pages. My own G+ biz page has benefited too . Let’s connect on Google+: https://plus.google.com/117631110100439879352