With the recent news of some Australian iCloud users being held to ransom after having their devices locked by a hacker gaining access to their iCloud account and using Find My iPhone, it's as good a time as any to enable two-step authentication on your Apple ID if you aren't already using it (though it isn't yet available in all countries).
This Apple support document explains how to enable the additional security precaution, what it involves and how it offers an additional level of security when it comes to managing your account.