Step 1 - Convenience / Basic Environment setup

For the most comfortable interacting with the system, I use/suggest several tools and programs.

Set the correct terminal encoding and keyboard layout

If you want to change the terminal and keyboard settings, simply use the dpkg-reconfigure commands and follow the gui instructions:

root@xubuntu ~/Desktop # dpkg-reconfigure keyboard-configuration
root@xubuntu ~/Desktop # dpkg-reconfigure console-setup

Limit sudo to a single group

Allow members of group chucknorris to execute any command after they have entered their password

root@jiffybox # groupadd chucknorris

Make sure the line

%chucknorris ALL=(ALL) ALL

is contained in the /etc/sudoers file.
Finally, add the desired user(s) to the group:

root@jiffybox # usermod -a -G chucknorris testuser