This is super simple to do with many people asking how we do it. This awesome feature makes it so that in search results for your site, your picture is shown alongside - demo. It's been shown that people are more drawn to results that have a person's picture next to them, and it's not at all hard to do for the additional hits.
The first thing to do before you set up the tag that you need is to register on Google Plus, you will want to make sure that you've given yourself a profile picture - this is the image that will display alongside the search result.
When you've got yourself a shiny profile picture, you need to add your site link to your profile in the Contributor To section, this is to prove to Google that you're actually related to the site, and not just being a fool.
Finally, you want to grab your profile link - for me that would be: https://plus.google.com/109699957362436337904/posts
Now we simply add a tag to the page header to show that we're the author for the post, we place a
link element within the
head section of the site, so using my above profile link it'd be:
<link rel="author" href="https://plus.google.com/109699957362436337904/posts">
Here on Codular we give each author their own author tag on their page, but don't add any author tags to non-article pages, for the sole reason that those pages contain information from all the different authors.
That should be it now - it can take a while for the changes to be reflected within the Google search results, but this is no different to the standard schedule that Google will use to index your site.
You can test that you've set everything up correctly by running your site through this helpful tool from Google.