New plugs, plug wires, keep tires inflated right, serpentine, good battery, not having a powerful radio, make sure a brake is not dragging... There are lots of things to try. Cruising in final gear is best of course, but if you are accelerating hard enough up to that gear you will see a lot of mpg loss. You might not see the same mpg as what is rated, since the EPA is in the pocket of auto makers (IMO anyways). Also use good gas.