I agree with those who say it's much too early for the OP to assess mileage. Wait until 10K minimum. And use Fuelly (see below) as opposed to trying to figure mileage from the dash computer. Pencil and paper (which is what Fuelly is, minus the pencil and paper) wins every time.
As for our Passat, we have made absolutely no attempt to break in, and we drive exactly the way we've always driven (limit in town, 10 over on 2-lane highways, 75 max on Interstates, using cruise control wherever we can). We are nearly at 20K, and on average exceeding the EPA rated highway mileage for this car. I'd say we're extremely satisfied.
That being said, there's no question that the biggest and easiest difference most people can make in their mileage is their speed. There are graphs on this forum that lay it out with crystal clarity just how much extra fuel is consumed as speed increases. The numbers don't lie.
The second biggest change many people can make is to watch traffic ahead, slowing down (I don't use the word "coast" advisedly here, I mean take right foot off gas pedal) in advance when it's obvious that a traffic slowdown or a stop sign or stoplight is coming up. Yes, you'll probably have some idiot on your bumper for the last few hundred yards, because many people come up to these situations and just stand on the brakes. As has been pointed out here, this wastes fuel and is hard on the brakes and other components of the vehicle*.
*What is now our second car is a 2004 SAAB 9-5 wagon with 165K on it. It has had one (1) set of front brake pads in all those miles. No calipers, no rotors, no nothing. That's it.