If you have been following some blogs via the Google FriendConnect "Followers" gadget, you can easily get the list of blogs you have followed so far. This will be so helpful to you in managing blogs you are following.
If you know the list of Blogs you are following, you can easily unfollow some blogs that you think no longer worth following.
Go to : http://www.blogger.com/manage-blogs-following.g to see the list now.
I hope it helps.