Driving style is biggest, closed loop doesn't help for miles from a cold start, so only helps on longer runs.
Keep well back from car in front, no need to brake then.
Often you can stop accelerating long before you usually do.
As soon as see red light back off, may piss off people behind, but no point hurrying to a stop.
From instant economy I found in last car would drop to 10mpg at the slightest acceleration from standstill and up to speed, so a quick boot up to speed using reasonable revs was much better than spending 10 times as long at twice the mpg.

Also, would like to find out about peak torque vs wind resistance/engine speed etc, as my M3 does 4mpg more according to obc at 80 odd than at 50 odd.