The Apple Watch automatically adds the 12 most used contacts from your iPhone. You can change these contacts on your Watch by opening the Apple Watch app and navigating to My Watch > Friends. On the Friends list tap Add Friend, then find and tap the contact card of the person you want to add. Only friends listed in your iPhone contacts will appear on the list.
One of the most useful Apple Watch features is being able to locate your misplaced iPhone. To ping your iPhone, swipe up on the Apple Watch display to access the Settings glance, then tap Ping iPhone. This will only work if your iPhone is in range of your Apple Watch. When the two devices are not connected to the same Wi-Fi signal the range is about 330 feet (100 meters) for a Bluetooth connection.
Update: Devices with iOS 10.0 or later installed now show recommended apps on your Lock screen based on your location. You can disable this feature by following these steps.
There are "over two million ways to see time" on the Apple Watch, according to Apple. This is due to the many features you can add to the 11 watch face designs. For example, you can adjust the color of the Chronograph face and add features like weather, stocks, battery power and more. Here's how to customize all the available Apple Watch faces.
The Apple Watch ships with its own Mail app for reading emails, but it can't be used to reply to messages. You can read entire messages within the app or read them in a notification. To receive mail notifications on your Watch you need to navigate to Settings > Notifications on your iPhone and make sure the Mail slider "Allow Notifications" is enabled.