You can actually get friends when you know more people. Just add them in your circles and they'll continue to rise. The same way you have more friends in facebook, you can have in google+.
Try to use your Gmail or other mail contact lists to gather the friends who are already on Google+ and add them into your circles. And even, google+ show you the recommendations or suggestions where you can choose the person to add into your circles. In this way, i have added around 500 people into my circles within 5 minutes by just selecting and dragging them to the circles.
I think you should be active on google+,add informative information on g+, circle friends related to your keywords.
It will not be an easy work. At present, most of the people are using facebook and they even don't have account in google+. Give times, when the amount of user will be high, you will find a lot of friends there. But at present scenario, you have to depend on the Google+ suggestions only.
?Just keep continue to working on G+,,,, contact the circle then you will definitely get the too many friends,,,,
You can connect with lot of people you know, send request to your friends and connect with friend's friends. Try to be in touch with many.