Getting fuel average in one day is difficult.
At-least drive a full tank to get more accurate results.
How many kilometers it has driven?
Engine oil should be of very low viscosity like 5w-20, 0w-30 or 5w-30. These oils gives best fuel consumptions. Use recommended oil filter. Match its code before installing.
Make sure its has CVT gear oil and its full.
Radiator has only Water or coolant? (if water then using good quality pre-mixed coolant is suggested).
Fuel it up from good station and mix 20~30% Hi Octane.
Change the spark plugs.
Get the throttle body cleaned.
Engine RPMs should be properly checked and set to ideal (I guess it should be in between 700~800).
Use good quality air filter. Very important.
Water closely that Radiator is not clogged with dust.
Alignment should be correct.
Wheel should be balanced.
Air pressure 26-28 psi (I keep it 26 psi in summer and mostly 28 psi in winters)
A/C AIR FILTER
Many people doesn’t care. But it has A/C air filter that need to be replaced as well.