Well, you can start following different Business Pages and find people, who to add to your cycles. This is probably the most effective technique. Usually, if you start following someone, there is a big chance he or she to follow you back.
You can try to buy targeted followers, but unfortunately it is hard to find a seller who offers real ones and not fake accounts.
interact with your circles... Social networking when used in IM requires you to be sociable... give + to others' post, leave comments, and all that...
If you can start following different Business Pages and find people, who to add to your cycles then you will improve your Google circle.
Well think that is the only way ( "start following different Business Pages and find people" ) to done it faster.. other way is to have great content to make it public and to hope that some1 will add you .. but that will go slow like hell.. 1-2 people per day
Well there are really some of the nice methods which you can surely use so to increase google+ likes, you can use this method with bad and good move. See, once I created free giveaway on one of my tech blog and then I asked my readers to complete few things which included Google+ likes to my same website + few social bookmarks and Facebook likes believe me I got 10k+ entries and guess what? I got 10k+ Google Plus likes to my website and Google Plus Page followers. Well, that was genuine giveway but you can start giving fake giveaways and can easily grab these exposure!
Add more and more people to your circle so that they will follow you back resulting an increase in your followers.