i found with every car ive had that making sure ur engine is running as good as possible is the key to fuel economy. always check ur coils and spark plugs r in good order, ur tune is spot on and always use a quality filters (oil,air and fuel) always replacing them at required intervals (or a little sooner).
oh and dont carry around crap for no reason. always remember to keep weight as low as possible. depending on how bigger concern economy is u may want to stop using the drive thru window, u'll save fuel and wont get fat from junk food