Drive the speed limit. Coast into stops. Use cruise control on the highway should save 15-20% on gas consumption. Not fancy but it works.
I have stopped driving except when necessary, and then I try to go out and do everything that I need to do for the foreseeable future. I am a mile from work, a mile from the grocer and close enough to most of what I need that I can walk or ride in 15 minutes or so.
Speed should be between 60-80kph. I saw in the news that studies show you will consume less gas if you drive with that speed. And also, do not have a tank full of gas because it makes the car heavier.