Also make sure your tires are well inflated. Even a little higher than the door tags say is good for fuel economy. If the door says 32 psi put at least 5 psi over that to get better fuel economy. In winter you may lose 5 psi becuase of the low temps. Don't warm it more than a minute in winter. Drive away slow on cold mornings and drive live Ms. Daisy's in back for the first mile. Engine will warm up faster that way. Consider lighter weight oil in the winter if you are truly cold for long periods os time. The owners manual will give you the cold weather oil options.(Less friction). Also, if you have a manual shift mode, use it to upshift as soon as you hit 1,500 or 2,000 rpms every time. Getting to the highest gear keeps rpms down and MPG up. Good luck! Hopefully it will break -in too and increase becuase of that. Winter is always the low MPG season, more air resistance, low tires, snow, winter fuel blends, thicker oil....etc.
I replaced the air filter, stopped running the car in the driveway or parking lot and am taking longer to speed up. I will have to see how things go but they seem to be improving. The warmer weather will probably help as well.
I am purchasing a Gauge that reads the data from any vehicles computer. All recent vehicles have an On Board Diagnostic port. ((OBD II) required by the EPA)This will allow me to see my instant MPG, (and many other things. The one I am buying is a little over 60 Bucks. (Ultra-Gauge). They seem to only sell over the web, It's worth a look.
Knowledge is power, I need to adjust the nut behind the wheel!