Pick any place on earth. Stand there with a GPS receiver. The signal quality and number of satellites that you're receiving a signal from will constantly change. There are six different orbits in the system, and each of those orbits has four satellites in it, and they each complete an orbit in 12 hours. The number of satellites that you can see and their position relative to you is constantly changing. As is shown here, there is no such thing as poor GPS coverage.
Poor reception due to the environment around you is not the same thing as poor coverage. If you're driving down a street that has a lot of trees with a lot of foliage above you that create havoc with your reception, that is completely different than saying you have poor coverage.
Now, as for you "doing it wrong", well... The only thing you could do wrong is place your device in such a position in your vehicle that it directly hinders its reception. If you have your phone well forward on your dash/windshield so that it has a clear view of the sky, and nothing is above it but the windshield and the sky, then you are not doing it wrong. If you have it sitting on the console between the front seats, and the only thing above it is the roof of the vehicle, meaning that it's lucky if any GPS signals reach it at all, *then* you are doing it wrong.
If anything goes wrong when it's got a clear and unobstructed view of the sky then it is either momentary GPS reception problems, momentary server connection problems (which has a remedy in the works), or some other server-side problem. As long as you give your phone a clear view of the sky, it's kind of hard for you to do anything wrong. Like I say, there's never less than six satellites in your line of sight no matter where you are on earth. And most of the time there's more than that. And you only need three to give you your location. As long as you give your phone a good viewing angle on as much sky as possible, which you do by getting it as far forward of your roofline as possible and under more windshield than anything else, it'll usually do a good job.