I got 82 MPG once in my Panda diesel. There was a couple last year who squeezed an average of 126 MPG over 3700 miles, it's fairly easy to do, it just depends how safe a driver you want to be. For example, you could turn your engine off down hills etc but you risk loosing braking power! You could follow big trucks closely on the highway but you risk not being seen or worse, going into the back of them.
My 82 MPG though was achieved with ease and was not risky at all. Start with turning off everything you don't need, lights, A/C etc and close the windows. Check your tyre pressures. Basically accelerate very slowly, as if there's an egg between your foot and the accelerator, same with the brake, avoid it if you can! Be very gentle with all the controls, the clutch too. Get into 5th or 6th gear at 30 MPH, don't worry the car will be fine. On long downward hills, come off the accelerator all together, but don't put it in neutral as this actually uses more fuel! Limit your top speed, i stuck to 40 MPH as it was a bendy road anyway.
Give it a go! The best i've had from my current car is only 51 MPG, but that's not bad for a performance car!
Another thing is to look at the person's history to see if their entries are consistent. I have seen quite a few entries lately where it's obvious they missed keying one in. If a person keys @350 miles and 29-30 mpg for a while and all of a sudden there is one tank at 700 miles and 59 mpg, that's a very obvious mistake.
It is nice to be able to communicate with others getting better mileage out of the same models of car. It would be easier if cars were seperated by transmission type, though.
Drive the speed limit. Don't accelerate hard, but don't be a puss about it either. If you use the resume for your cruise control, that will give you an idea of where you should be.
Keep your tires inflated to at least the minimums. I usually run mine 3-6lbs over, for a firmer ride and it helps the MPG.
Run synthetic oil. All of my vehicles do and it helps. Run the appropriate weight per your manufacturer. I run 5w-30 winter/10w-30 summer. 5w-30 is what all of my vehicles call for. But 10 gives it better protection during the hotter months. Those that use diesel fuel obviously have different standards, etc
Keep the stuff you don't need out of your car. Less weight means less work for the engine.
Other things are just common sense. Don't sit with your car idling for any reason. Traffic lights etc, fine. But just because you are going to run into the store real quick doesn't mean you can't shut the car off. I always shut it off, even in the winter. I don't warm it up either when its cold but I go easy for a bit till it warms up.
I don't drive the best MPG vehicles, but I get good results keeping my habits uniform. Though its really hard to do with my Z. lol
Me! I manage it All the time. I have a scooter - 73 mpg and a transit van for business - 25 to 30mpg. diesel. I also have a bicycle that uses no fuel at all. Just porridge. I just use the most appropriate vehicle or public transport and my fuel bills are tiny.
I'm averaging over 80mpg on a daily basis and around town. On a long run I easily top 100mpg. The best I've had was 120.2mpg door to door (including the town work) between my home in Doncaster and Uxbridge.
The car? An Audi A2 1.2Tdi (3L) only ever sold in Germany and discontinued by Audi about 4 years ago.
I've had it from new and done over 105,000 miles now. Overall average is 90.2mpg according to the computer (which I've checked as accurate).