The easiest way to sync files with Google Drive is to use insync client which provides seamless user experience, customer support and enhanced functionality.

Installation is quite easy as you can download packages for every major operating system directly from the Download Insync for Windows, Mac, Linux and mobile page.

Most important features like multiple accounts, sharing, documents conversion, folder synchronization and file manager integration are described at the Insync features tour page.

I need to mention that there is Raspberry Pi package available (although beta version).