Step 1: Items Required
Step 2: The Method
You can do this one to two ways. You can either have two devices, one with the target, the other on your person, which is the most preferable method because it allows you to be mobile as well. Or, if need be, you can have one phone on the target and see up to date locations of where it is from your home computer.
The two phone method, again, is more preferable especially when you're following the target or wish to give them a surprise visit. But the one phone method will also work if you don't have an extra.
Of course though, both devices don't need to be yours. Lets say you want to keep track of where your kid is going you could easily install the application on the phone you've paid for and see if their tell you the truth of where their going or not. Or you might easily forget your phone in your spouses vehicle and see if their lying about their whereabouts as well.