To tag friends in posts, type "+" or "@" followed by their name. You'll see an autocomplete drop-down menu show up as you type their name, which presumably includes people in your circles and extended circles.
Your friend will be notified they've been tagged in a post, and post visibility will automatically be set to just that person. Don't forget to add more circles and friends (if you want to) before sharing.
Permalinks come in handy for sharing and cleaner viewing of single posts. Just click the timestamp of any post and you'll be taken to a new page displaying just that post.
Oh, the irony. To share a post with your Twitter or Facebook network, use the Extended Share for Google Plus Chrome extension. Upon installation, you'll see a new option ("Send to...") below each post in your stream.
Here's a nice feature for any on-the-fly photo editing. Go to your photos (accessible via your profile), select a photo. Click Actions > Edit photo, and you'll be presented with several photo filters. Scroll through other photos in the album for consecutive editing.
To send a message to just one friend, tag him or her in the beginning of a post and let them know it's a private message. Then, comment on the post to establish your own private thread.
With this setting, you can let people e-mail you directly from your profile. Head to your profile, then select "Edit profile".
Below your profile photo, you'll see a grayed out "Send an email." Click it, and check "Allow people to email me from a link on my profile." Then adjust the privacy settings below.
