Profile name: Pick a profile name as close to your business or website name as possible. When you have at least 10 followers, you'll be able to create a custom URL based on your profile name.
Profile Picture: Your profile picture will show across the web, so be sure it;s professional and recognizable! Perfect image size: 250 x 250 px.
Cover Photo: Perfect size for Google+ header is up to 2120 x 1192 px. Take advantage of the large space! Choose picture that relates to your business or your industry. You can even use animated GIFs as a cover photo.
People: Be sure to enable "show people who have added you to their circles", which will impress people who visit your page.
Occupation: Keep it short - a sentence or two about what you do and where you work.
Skills: Don;t be shy! Everything you are good at (or want to be seen as good at) should be listed here. Use at least 5 strong keywords.
Employment: Highlight your career history, providing 2-3 sentences per job.
Education: Listing your education will further highlight your history, and allow Google+ to search for more people you may know.
Contact Info: Always include contact information! Even if it's only an email address, list the source you check most frequently so people can contact you easily.
Tagline: Use 10 words or less to describe yourself, and include keywords!
Introduction: You can be as brief or lengthy as you like, but you want to make sure your introduction is engaging and lets people know what you're about.
Bragging rights: Exactly what the title says: Got something to brag about? Include it here as text or links.
Places: Listing your zip code will include a map of where you're located - and where you've been - on your page. While not a necessity for a strong Google+ profile, the more information you've, the more valid your profile will appear.
Basic info: Most of this will be auto filled when you create your account, but you can choose how much personal information you want to display to your circles.
Other profiles: Got any other profiles? Blogs Websites? Add them to improve your visibility across multiple platforms.
Contributor to:Any other site or blog your write for should be linked to their "about me" page here to authenticate your authorship. Links: These can include recent blog posts, featured publications, whatever you think represents you well. Show them off!