For this to work, you will need to have access to an account with sudo privileges already. This has been tested on Ubuntu 14.04 but will most likely work on all Debian based distributions.
If you are creating a new account then you can use the following command
sudo adduser <username>
This will then create that user. You can then use the following command to add that user to the sudo group.
sudo adduser <username> sudo
You may need to logout/in for this to take effect.