If you updated the Arduino IDE to the latest version (1.6.3), you may have noticed a great improvement: a new tool for library management.
In past indeed there was no a single place where you may found almost all the available libraries and the installation process was not so easy… with the new IDE instead if you click on Sketch – Include Library – Manage Libraries you can access the new Library Manager.
This tool allows to search for a library among the available ones (in the example I’m looking for a library to use a real-time clock) and to install it with just a click:
The library is downloaded and installed in few seconds:
and it’s immediately available to be included in your sketch: