Welcome aboard!
You've the same body style as me, only a year younger. Is your car automatic, or manual?
What you're aiming for is prudent.
Driving style, you'll be able to monitor better with the Scanguage.
Some of the driving styles advocated here are more relavant to gas engines than diesels. The modern electronic injection diesels, like the TDI, will stop pumping fuel when you are off-throttle coasting down stops, or down inclines. That's free savings there, until your engine drops closer to idle speed - 1200rpm and lower for the TDI, it'll start fueling the engine to maintain engine speed. If you're not doing it already, use this to your advantage, it's a freebie.
From my own experience, TDI engines seem somewhat prone to air issues. Namely, keep...
- the snowscreen on the air filter clean
- the air filter clean (depends on how dusty it is, for me)
- the MAF (Mass Air Fuel) sensor is operating correctly so you get accurate readings
Even with a bad MAF sensor, I've still been able to get good mileage, but highway omph is lacking when the ECU uses it's backup fueling pattern and goes into "Limp" mode.
And, with the nature of the little diesel, engine tempurature (coolant temp) will also affect mileage. This, and winterized diesel is a big factor with short drives in the winter months.
Between MAF sensor issues and me having trouble keeping a consistant fuel point, my SG readings tend to fluctuate from pump receipts and my trip odometer readings, so, don't be too alarmed by that. Use it as a tool to figure out relative efficencies on your usual commute, until your ScanGauge is calibrated.