To get better fuel efficiency, this is what I do..
I change the pull the spark plugs make sure they're all burning nice and hot. If not, non sufficient spark will cause less power output causing the engine to waste fuel. Next I pull out my air filter and clean it with compressed air. Then I clean out the throttle body to allow more airflow.
Other key things that I keep in mind is that, on OBD2 equipped vehicles, running higher octane gas will help with fuel economy because the knock sensor will compensate timing for the higher octane fuel. Another thing, I try to drive around 55-60 mph only if possible because fuel efficiency on vehicles is, from what I know, designed to work best at that speed.
*** Just my thoughts..