I've had my 2012 Sonata Hybrid for about 8 months now and have found the best way to maximize the MPG.
At first I tried "hyper-mileing", putting it in neutral going down grades, etc. that didn't give me the mileage I expected.
After lots of experimenting, I've found the best way is to use the cruse control as much as possible. I set it for the legal speed and if I need to put on the brakes for any reason, once I accelerate back to 25MPH, I press the resume button on the wheel. The efficiency of getting back up to the set speed is much more then I can do by food pedal. I call it "Thumb Driving" as I can drive for long distance without using my accelerator pedal. This works on highway and country driving (where speeds are between 35 - 50 MPH).
I've been averaging 38MPG overall, and that will improve with time as in the begging I was averaging about 33MPG. Try it.