Prevent anyone from sending you an email
By default, anyone viewing your Google+ profile can send you an email. Although your email address is not actually shown, this could open up the potential for lots of unwanted spam.

Just head to your Google+ settings and navigate to the Profile and privacy tab in the left column. From there, click on the Edit visibility on profile button in the Google Profiles section, adjacent to Public profile information. Next, click the Send an email button under your profile picture. You can choose to disable the email option completely by unchecking the option that allows people to email you from a link to your profile. Otherwise, you can selectively choose who can email you, such as only people in your Circles.
Modify your email notification settings
One of the things that has kept me coming back to Google+ are email notifications. Similar to Facebook, Google+ does a good job of getting users to return when someone mentions them in a post or adds them to their circle. However, since Google+ is integrated so deeply across many of Google’s core services via the new “black bar” that adorns the top of Gmail and Google search, there’s no need to have email notices sent to your Gmail inbox as well.

Head over to your Google+ settings once more and here you can modify the settings that determines how email notifications are delivered. I unchecked all of the options, but that’s purely because of personal preference.
Flip through profile photos when viewing them
When you visit someone’s Google+ profile, you can view all of their uploaded photos from the Photos tab. However, if you just want to look at their profile pictures, simply click on the profile picture to rotate through each one.
Download the Google+ Chrome extension
If you want Google+ notifications viewable from anywhere even when you aren’t using a Google service, check out this Google Chrome extension. It’s essentially the notifications box you see in Google+ accessible from your Chrome browser.
Copy one circle into another
One of Google+’s most highly touted features is Circles, which lets you organize people in your life into different groups. To copy one circle into another, first visit Circles. Then, click on the circle you want to copy. Next, select View circle in tab. In the top right corner, click on More actions and then the Select all link. This highlights all members of your circle. Now, simply drag and drop the selected members into another circle.
Source: Chris Cartland
Utilize shortcut keys
Feel free to share any I may have missed in the comments section below.
J = scroll down one post
K = scroll up one post
Q = jump directly to chat
Return = Start Comment
Tab and Return = End Comment
Disable resharing on posts

When you share something on Google+, you can define which circle of friends to share it with. If you are sharing something with a circle dedicated to your closest friends, you can disable resharing of that post. First, the post must be shared to your circle. Then, click the arrow in the top-right corner of the post and select Disable reshare.
Format text in your posts

Format the text in your posts by surrounding words according to the following: *bold*, _italics_, and – strikethrough -.
Mute annoying posts
One of the annoying things about Google+ right now is that old posts seem to be pushed back to the top of your feed when more people start to comment on it. Luckily, you can mute the post by selecting the arrow in the top-right corner and select Mute post.
Leave Google+
Arrrrggghh! This is madness! Google+ is worse than Buzz and Wave!
If that is how you feel after using Google+ for the first time, Google provides a tool called Google Takeout(no, it has nothing to do with food) that lets you download an archive of all your data from Google+. As Vic Gundotra explains, “It’s your data, your relationships, your identity.”
Vanity URLs
You might’ve noticed the horrendous looking profile URL in Google Plus. It looks something like this:

Not very informative, and you’re probably thinking, there must be a vanity URL option, right?
Nope.
Meanwhile, there is a temporary solution to make your Google+ profile URL pretty. Check out http://gplus.to and enter a username for yourself. Mine is http://gplus.to/tonyhue.
Hat tip to Matt Cutts for providing some of the Google+ tips.
