How to install clearlooks theme on Ubuntu 12.04LTS

-Check GTK version
~$ dpkg -s libgtk-3-0 | grep '^Version'
Version: 3.4.2-0ubuntu0.5

Download the packet for different GTK version

(Clearlooks-Phenix 1 for GTK 3.0 and 3.2)

(Clearlooks-Phenix 2 for GTK 3.4)

(Clearlooks-Phenix 3 for GTK 3.6 and newer)

~$ unzip projets-divers-clearlooks-phenix-4d2a946df42129a279fbef41ffe60b6ef543d46b.zip
- Extract the archive.

- Rename the extracted folder to `Clearlooks-Phenix`.
~$ mv projets-divers-clearlooks-phenix Clearlooks-Phenix

- Copy the folder `Clearlooks-Phenix` in the location:
~$ sudo cp -r Clearlooks-Phenix /usr/share/themes/
     
- Install gonme-tweak-tool

~$ sudo apt-get install gnome-tweak-tool

- Then, choose Clearlooks-Phenix theme with tweak-tool:
by setting *Theme  > GTK+ theme* > Clearlooks-Phenix

See the picture below(looks much better):

More details see here:
http://gnome-look.org/content/show.php/Clearlooks-Phenix?content=145210