REBOOT YOUR PHONE EVERY WEEK
According to the National Security Agency's (NSA) "best practices" guide for mobile device security, everyone should reboot (totally shut down your phone and restart it) their phones at least once a week. Neil Ziring, technical director of the NSA's cybersecurity directorate, was quoted in the AP as saying, "This is all about imposing cost on these malicious hackers." While it won't stop a sophisticated hacker, it will make them work harder to maintain access and steal data from your phone. The reason is that the latest malicious software typically targets your phone's root file system. But the newest phones can detect and block such malware during a reboot.
Make it a weekly habit, maybe even set a calendar reminder to do so, to turn your phone off and on.