Use 0w-20 engine oil grade, meeting latest API SN / SN Plus, and / or ILSAC GF-5 criteria. Prefer fully synthetic, from some reputed brand, and 100% genuine and original. Replace oil + oil filter after every 5,000 Kms. Use engine flush before switching to new oil brand and grade.
0w-20: Caltex Chevron, Shell, ZIC or Total Quartz 9000 Future Series.
Clean spark plugs, throttle body & MAF sensor, i.e. engine "tuning", if required. After this, reset ECU by removing one of the battery terminals for 15-30 minutes, and reconnect again. Follow "Idle learning procedure" and start driving.
Replace / clean air filter and AC / Cabin filter, if dirty.
Get all the wheels balanced and aligned, if not done recently. Keep tires inflated properly as per OEM recommendations.
Always drive with light foot and soft pedal. Accelerate / Decelerate gently. Apply brakes softly.
Follow maintenance schedule as suggested by the OEM.
Use Shell, Total or at max. PSO fuel, but from company operated & maintained fuel stations only. And I would say, no need to use High Octane. Just use regular unleaded gasoline by Shell.
Etc... Etc...
By following above steps, I am quite hopeful that your fuel efficiency will become better. Try these steps, and share your feedback here.
