How do I install themes?

Go to 'System --> Preferences --> Appearance' and press "Get more themes online".

Download something you like and then drop the file you downloaded to the Appearance window. The files you download are usually in the Downloads folder.

You can download other themes from other websites, just drop what you download to the Appearance window and in a few second you will have your new themes in Ubuntu.

That tutorial is for installing themes from one specific designer. Check out the site www.gnome-look.com for all sorts of other themes. Use the GTK2 filter to find ones better suited to Ubuntu's default Desktop Environment.

Most themes come in a .tar.gz format. To install them simply open up the Appearences app. (System > Preferences > Appearance) and click the themes tab. Once there, click on install new theme and a file browser should open. Navigate to where you saved the (theme).tar.gz file and select it. Ubuntu will then install the theme for you. If the install instructions happen to be different, the author usually posts them on the theme download page.

If you're looking for some cool themes, check out Elementary, Victory, and the Faenza Icon Set. They are my favorites!

Best place to download themes (imo) is http://gnome-look.org Click on the link that says GTK2.x in the left hand column. Find one that you like and download it Go to System->Preferences->Appearance and click the install theme button. Browse to your theme and install. That's all there is to it :)