I traded in my 2007 Mitsubishi Galant w/120,000miles @30 MPG for my First Generation Honda Insight w/58000 miles @ 75+mpg. Add in hypermiling on my way to work, and I am averaging 85-95MPG on that commute. I don't do nearly as well when driving around town- but in my first 1000 miles I have averaged 75mpg. This car is crazy- over 700 miles on my first tank, and when I filled it up the bill was under $30. ($3.09/gallon for 9.something gallons.)
This car is built for it, but I do make sure that the tires are pumped up, but otherwise, everything is stock. The biggest drain is acceleration, so what helps the most is minimizing stop and go. Once at speed on relatively flat terrain, it is pretty easy to average 90+ in this car.