To block your phone from being tracked, turn off the cellular and WiFi radios (turning on “Airplane Mode” does this). Disable your device’s GPS radio or turn off “Location Services.” On most Android devices, you can also shutdown the phone and remove the battery. It isn’t possible to remove the battery from an iPhone. As you might be aware, doing any of the above will severely limit the use of your device. (Um, especially the part about turning it off.)