By demonstrating your professional interests and skills on Google+, you increase your chances of impressing a contact (who might then recommend you for a job) or even getting noticed by a recruiter. Here are some things you can do to establish your professional presence on Google+.
The most direct way to get the attention of a contact or recruiter is to send them a message, or a "hangout," introducing yourself (or, if you've already met, you can send a message saying hello and reminding them how you met). If you want to ask the person for a favor in your message (job advice, a recommendation, etc.), just be sure to announce your willingness to help them as well (for example, "I would be more than happy to write you a recommendation as well.").
Post on your Profile
You can post a number of items on your own profile, including photos, videos, hyperlinks, and text. You can post items that demonstrate your knowledge of your field; for example, you can post an article related to new trends in your field, and comment on the article. These posts will demonstrate that you are knowledgeable and up-to-date in your field.
You can also post links to your recent work, including links to your blog, articles you wrote, etc.
Be sure to make these professional posts public, so people (recruiters, people in your industry, etc.) can see them.
If you decide to include these professional posts, keep your personal posts (photos from family trips, comments about your day-to-day life) private; only show them to people in your "family" and "friends" circles. This way, when a recruiter looks at your profile on Google+, he or she will only see your professional posts.
Comment on Posts
You can also comment on posts that other people have made. If a contact posts something about your field of work, for example, you can add a comment or response to demonstrate your own knowledge of (or interest in) the field. Don't have anything specific to say? You can also +1 a post, which is similar to "liking" something on Facebook. You can also share a post someone wrote on your own profile.
Host a Hangout Party
Google+ also allows users to host a "hangout party," or a group-video chat. If you are knowledgeable in a particular topic (for example, current online marketing strategies), you can invite your contacts to a hangout party in which you will give a mini-lecture and then engage in conversation about the topic. Invite employers for whom you are interested in working (or contacts who work at a company in which you're interested) to demonstrate your knowledge and potential value as an employee.
To get started, download the hangouts plugin to your computer. Before you start a hangout, check your settings to make sure that your webcam and microphone are working correctly. Visit this hangouts page (you'll need to be logged in to Google+ to view it), click cancel, click the gear (settings) at the top right side of the page. You'll be able to test your microphone and adjust the position of your webcam, if necessary, based on what you see on the screen.
To be sure your ready for prime time, ask a friend or colleague to practice with you. That way you'll know that your video and audio are appropriate for a professional conversation.
Create a Page
If you own a company, or are a freelance worker, consider creating a page for your company or brand. This will help you develop your company's online presence, and allow you to gather an online following.