How to identify the "early adopters" among the lovers of your brand?

Create a Google+ Page.

Create a circle named "early adopters".

(no any other action here, just wait...)

Add to that circle the first 1,000 Google+ users that add your page to their circles.

Now what?
Reward those users. Give them special treatment, they are special. Reward them with exclusive content; make sure they know it is exclusive content and they'd love your brand even more. Listen to them, they'll teach you on how to use Google+ Work with them and they'll be your brand ambassadors in Google+.

Take care
Javier Arias González