Install Gnome Tweak Tool : This helps in manual & better customization of system.
~#apt-get install gnome-tweak-tool
Considering here changing theme using this last install.
Visit this and select the theme you want and which support your
Either download it in browser or download via wget.
Wget helps to download file directly using terminal. For my selected theme:
Before running wget I have created a folder using mkdir and changed directory to that
folder using cd .
Seems it is a tar.tz , we need to unzip it:
~#tar -zxvf 147061-Gnome-Cupertino-2.1.5.tar.gz
(tar -zxvf is used to unpack and tar zcvf is used to create a tarball)
Next we need to copy the theme file to the location where system stores the themes.
~#cp -r Gnome-Cupertino /usr/share/themes/
Now open Applications–>System Tools–>Preferences–>Advanced Setting , select Theme Tab and change to the new theme.