- Replace your Blogger profile with your Google+ profile. You can do that here.
- As you step through the authentication process, you'll be asked which of your Blogs you want to link to your Google+ profile. Most of us have only one, and it should be checked by default. If not, click it.
- Now, from http://www.blogger.com/home, go into your blog Settings. Then go into Posts and comments.
- Look for Share to Google+. Make sure it says Yes.
- If you don't see Share to Google+, you may have to click on the Gear in the upper right, and choose Connect to Google+.
- Click Save Settings in the upper right.
- Now, whenever you click Publish on your new Blog posts, you'll be prompted to share it via Google+.