Ad Profiling
Privacy > Advertising
You will see "Limit Ad Tracking". Advertisers want to personalize ads for you, but setting this on (green in iOS 7) will maximize privacy.
Location Profiling
Privacy > Location Services > System Services
These three settings should be turned off:
Frequent Locations
Location-Based iAds
Diagnostics & Usage
Safari Tracking
Settings > Safari
Turn on the 'Do Not Track' setting (set it green in iOS 7).
For more information, please see this ZDNet blog post:
http://www.zdnet.com/four-privacy-settings-you-should-enable-in-ios-7-immediately-7000020902/
Some additional preferred iOS settings
I don't access the Control Center from the lock screen, so I turn this off.
Settings > Control Center
I have noticed a big difference in batter life by turning off Background App refresh for most apps.
Settings > General > Background App Refresh
This is an obvious preference, but Apple decided to not make the battery percentage indicator a default setting.
Settings > General > Usage
