ToxicBunny
Oi! Leave me out of this...
You tyres being pumped slightly harder (at say the "full load pressure", but note that ride is slightly harsher and braking distance is more) and your car being polished will increase efficiency.
Both of those are done.. within reason since I drive a 13yr old 2.5TDI double cab...
Then you're an exception. When driving today, look at how other people drive, then come back and tell me they drive conservatively.
Most of the people I know, do drive conservatively.. because we are all acutely aware of the price of fuel.