PC Magazine highlights a great list of protective techniques:
Android – Best Security Practices
QUOTE: Any Android user concerned about securing the data on his device should make sure the following Settings are turned on:
1. Enable Lock Screens: Under Settings\Security. Enable Face Unlock, Pattern, PIN, and Password to increase physical security to the device. Slide doesn’t do much.
2. Disable USB Debugging: Under Settings\USB debugging. When enabled, the data on mobile devices can be accessed without first passing a lock screen challenge unless Full Disk Encryption is also enabled.
3. Enable Full Disk Encryption: Under Settings\Security. This will prevent even USB Debugging from bypassing the lock screen.
4. Maintain Device Up-To-Date: Ensure the device is current with the latest official software. Unfortunately, users are largely at the behest of their carrier and cell phone manufacturer for this, but when you are finally prompted to upgrade your operating system, do so. Using only official software and keeping devices up-to-date is the best way to minimize vulnerabilities and increase security overall.
BONUS: Stick to official app stores. This is far less likely, but an attacker can also discover your PIN lock (which is necessary for him to root your phone) if you accidentally install a malicious app that records your personal data, including PIN. Most malicious apps are distributed through