67pmg over two tanks (2nd tank filled to tippy top, so this should be a fair estimate)
feather foot (egg between pedal and floor)
higher RPM when necessary to avoid WOT
higher RPM going up hills to avoid WOT
steady throttle whenever possible
feel for lean burn
Unless I've made some error in my calculations or these two tanks were somehow a fluke (they also had 30 miles of high speed driving: refer to my gas log) than 70mpg doesn't seem like an impossibility.
stock 1993 civic vx with more ground clearance from larger tires and missing front spoiler/lip thing for aero. Right size tires and replacing front lip thingy could improve things slightly.