Can't find your phone or looking for a family member? Use Family Sharing and Find My iPhone!
Updated April, 2017: Updated screenshots and steps for iOS 10.
Family Sharing not only lets you share iTunes and App Store purchases, but it also makes it easier for you to track all the devices in your family with the help of Find My iPhone. So next time mom can't find her iPad or dad leaves his iPhone at Starbucks, anyone in your family can help find it!
How to track an iPhone or iPad with Find My iPhone and Family Sharing
You'll need to have the Find My iPhone app installed in order to track devices in your Family Sharing group. If you don't already have it, you can download it for free via the App Store. Each device must also be running iOS 8 or higher and support Family Sharing.