This guide works for the gnome desktop manager (used by Ubuntu and other Linux distributions).

First we go to Gnome-looks. This is a large collection of themes and other artwork that can be used to make gnome look any which way you like. From there we select and download a theme. Since many people have asked what theme I use, I chose my theme, SlicknesS-black, for the example. Once we’ve downloaded our theme and saved it to the desktop, we will then extract it to the desktop.

Once it is extracted, in the terminal we enter the following commands to copy the theme files to the shared theme directory (where the themes manager looks for it) and change the permissions to make it available to all users of the computer:

$ sudo cp -r $HOME/Desktop/SlicknesS-black /usr/share/themes
$ sudo chmod 755 /usr/share/themes/SlicknesS-black/Sluckness-black.jpg

Remember, file and directory names are case-sensitive in Linux, so be careful to use the correct case.

Next we open the theme manager (in this case System -> Preferences -> Appearance -> Themes) and we should see our new theme listed there!

For Ubuntu users only – you may notice if you choose to install SlicknesS-black an error that states the engine “ubuntulooks” is not found. If that is the case enter the following command in the terminal to install the missing theme engine:

$ sudo apt-get install gtk2-engines-ubuntulooks

Enjoy your new theme!

(The wallpapers I use can be found at beautifulfractals and are available under the Creative Commons license)