I just hit 30+ MPG with my Mustang for my last two fill-ups. I've averaged over 28 MPG with it since my first fill-up, with a low of 24.98.
My best ever until the last 2 fill-ups was 29.956 MPG last August.
The only change was reprogramming my pcm with a Hypertech Max Energy power programmer with the 87 octane performance tune 196 miles before the first 30+ MPG fill-up. I don't know yet if the performance tune caused the higher MPG, or if my engine and tires are more broken-in at 14K miles. I'll do an A-B-A test after a few fill-ups.
I haven't made it through a tank yet without hitting 100% throttle at least once. And I've only made it through about three tanks without barking the tires shifting into second.
This was all commuting between home and work, with a weekly grocery run. Approximately 70% highway, 30% stop-and go.
My 235/55ZR17 Pirelli P Zero Nero's are inflated to 32 PSI.
There are no aero mods to the car.
My only hypermiling technique is avoiding the brakes and utilizing DFCO. (I do a lot of downshifting to decelerate.)
No EOC, no P&G, no DWL, no drafting, no engine-running coasting.
I set the cruise control at the speed limit on highways.