How do I fine-tune user privileges?
Solution 1:
Install the gnome-system-tools package from the Ubuntu Software Centre (or use
sudo apt-get install gnome-system-tools
in a terminal). This will install the 'old' users and groups tool.
To run it, search for 'admin' or 'user' in the Unity dash and choose "Users and Groups". Alternatively, you can run 'users-admin' in a terminal.