For good fuel economy, you have to change your driving style like no hard accelaration.
If you are approaching on signal, never drive with acclerator pedal pressed and then hard brake. But take your foot off from accelarator and let your car criuse to signal and mean while your signal may be open.
Try to shift gear early with light foot.
Never shift to nuetral when drive to slope like going down on bridge. but drive in high gear with out pressing gas pedal. It will save petrol.
Maintain good tyre pressure.
Drive at high speed may need more force to counter air draging. Drive at 100kmph may take 10 min extra to reach destination compared to 120kmph speed but it save alot fuel.
On motorway drive car with windows closed and AC can be used as requirement. If AC is used set cooling temp close to normal for rapid triping.
Use regular petrol. Hioctane may not give good fuel average in low fuel comression car.
Lastly drive car with 2000 to 2200rpm range max for any gear to get good petrol average.