U are getting 14 kmpl in Civic, thats really surprising as i thought that civic's FE would be around 9-11 kmpl. My City is giving me around 13kmpl. How you drive dude?? Thats really an amazing figure.
Well you would be amazed what the i-vtec engine can deliver, but i must say the hard part is the restraint, here are a few things i do :-
1) Good anticipation and less braking , lot of coasting where possible.(you can call me a boring driver generally)
2) Never over rev(it is very easy to do that in a city/civic and you wont even recognise it), sedate driving, drive at 90 at the expressway in top gear( its very difficult doing that in the civic i must admit) - keep your right foot very light :)
3) Keep the oil filter and oil clean and always at level.
4) manage gear changes at optimal speeds for fuel efficiency.
I have known civics giving even 17-18 kmpl when driven even more sedately not exceed 60-65kmph. The best i have got personally using the tankful method is 16.5 not exceeding 85kmph. Its also to do with the fact that i do a lot of expressway driving at leisurely speeds. In the city only cycle i would get about 11.5 - 12.5 kmpl. All of this with the ac on most of the times.