2003 Honda Accord fuel efficiency?

I bought a 2003 Honda Accord this past summer its a 4 cylinder coupe with approx 230000 km and during the fall months i was only getting about 480 km before the gas light goes on and thats with mix highway and city driving and i usually drive the car no more than 110 km/hr on the highway. My friend purchased the same car, same year with 200000km on it. His car gives him about 540km before the light goes on and he drives his car 120-130km on the highway also with mix highway and city driving. I recently did a tuneup where i changed all 4 spark plugs and i also changed the filter. I was thinking of resetting the car to factory settings by removing the battery terminals.

Is there anything else i can do?

Added (1). Also both cars are the same year, automatic, same trim (probably doesn't make a difference) and his just has 30,000km less than me. We also calculated that if i fill up with 54L of gas ill have only driven 480km and if he fills up and puts in 54L of gas his odometer reading is at 570km

Add a K-&-N air filter and you can get about 4 K per gallon better economy.

Are they EXACTLY the same car?

A different gearbox or dif ratio might account for that sort of difference. Manual vs Auto?

Or even driving styles. I can get 20% better mileage out of my car, just by pretending their is an egg on the gas pedal, and trying not to break it.

Or where you drive. 90% open road, vs 90% city traffic? That will make a huge difference.

So if you lead foot around town in an auto model, and your buddy drives a 6 speed manual on eggshells on the open road, the difference will be even bigger.

Make sure your tires are inflated, even over inflated. Drive very gently in town. Get rid of any dead weight in the trunk.

Just be aware that all drivers are slightly different, all cars are slightly different and especially, that all gas lights come on at different stages of emptiness