Every week, it seems, there is a question thread on the Forum, about someone's inability to stop following a blog. Although Blogger has changed from 'old' Blogger to 'new' Blogger, and seems to be favouring Google+ circles, Stopping Following is still relatively simple to achieve. It's a 4 step procedure.
Firstly, Step 1 - On your Reading list, click the little gear wheel on the right-hand side of your screen. Wait for the screen to display the list:
Step 2 - Select the blog you want to stop following, and click on 'Settings'
Step 3 - Click on 'Stop Following'