If you are running Elementary OS, you should have this Elementary Tweak application to tweak your Elementary OS. Elementary Tweaks has various tool to change and modify the appearance of your Elementary OS. This tool will help you to change the icon theme, Window decoration theme, Interface theme, Cursor, animations and some other things.
To install Elementary Tweaks on Elementary OS, add the official PPA to your system and install it. Do this command on Terminal:
sudo add-apt-repository ppa:versable/elementary-update
sudo apt-get update
sudo apt-get install elementary-tweaks
For more PPA, please visit my PPA Collections.