Some mpg food for thought:
1) In addition to staying on top of all other mechanical maintenance, if you advance your ignition timing you'll get both better power and better mileage, just don't advance it so far that your engine pings, or so far that you don't pass your smog check (I'm in CA). Related: if you use higher octane fuel, you can advance your timing further before the engine will start to ping.
2) Aerodynamic drag increases approximately linearly below 45mph, but starts to increase exponentially above 45mph. So, as many here have mentioned: slow down your highway driving and your mpg will improve.
3) If you can figure out how to shed weight reasonably, this will improve your mpg.
4) This last tip came from a tire & alignment technician with 25-30yrs experience: Increasing tire pressures by 5-10psi (even going over your tire rating) may give you some mpg gains. This is also counter-intuitively good for driving through the desert so that your tire sidewalls flex less to prevent blowouts. It is the flexing combined with the hotter road that causes blowouts.
