Fuel efficiant and powerful car

I have a Datsun go, 2014 model, this is the only car in its segment that is offering 1200cc engine. it is a powerful car. ac is good, tire size and suspensions are not up to the mark but still does the work quite well. the initial fuel consumption in the first 10 thousand km was 12km/L in city 14 km/l in the highway but after 10 thousand km. I have seen that fuel consumption has improved a lot. steering is very nice and the boot space is very very spacious besides that the door also offers space for bottles and maps. yesterday I filled my car tank to full, air pressure at 30 and I drove from Delhi to Agra to Fatehpur Sikri and then return to Delhi, it was a 502kms trip in total and I filled my tank again to full which was 28.1ltrs something and I drove it ac on all the time soo the average fuel consumption was 17.8 something which also includes city traffic in Agra and many places. tip: always drive Datsun GO at less than 2500 RPM. it has a digital meter soo it is easy to see it.