ICON THEME
Take a look at two Thunar windows in the screenshots. I have applied “AwOken” icon set (its name is really written like that, not a typo)
To install a icon theme, either install via PPAs or copy (the extracted) icon folder directly to /usr/share/icons or ~/.icons
Adding a PPA is often frowned upon, but since the PPA for AwOken theme is really popular. The risk is low, I think ;) !
You need to install software-properties-common to be able to add PPA using command line, to install it:
sudo apt-get install software-properties-common
Here is how I have installed AwOken icon theme, as guided here:
http://gnome-look.org/content/show.php/AwOken?content=126344
sudo add-apt-repository ppa:alecive/antigone
sudo apt-get update
sudo apt-get install awoken-icon-theme
AwOken is a special theme that have it own script to customize itself, here is the instruction given by the author, skim through it and you will see how awesome it is: Installation and Instructions (PDF)
Or if you want to learn by doing, below is the command to trigger all the options. The instruction a long the way is easy to understand and follow:
awoken-icon-theme-customization
Apply the icon theme.
Open Lxappearance to change the icon-theme to AwOken.
Here is how the icon theme is on my system: