In order for the phone to be
registered for development, it also needs to be browse-able in File Explorer when the phone is connected. In my experience, the most common problem is assuming that any USB cable is compatible when in fact some cables are only useful for charging:
Windows Phone 8 is not detected by your computer
When there are problems you may see the following screens:
When the phone is properly detected, you will see the following:
Upon clicking "Register", if your phone is also connected to the Internet, you will see the following in moments and be able to deploy your applications to the device:
