1. Make fewer trips
Did you know that when you drive a car that has been parked for a few hours, the engine is cold and it uses much more fuel for the first five miles or so? Ideally you'd combine all your daily errands into one big trip. Often that's not possible if you have to pop out during the day to drop off and collect the family, but try not to go out separately to do the supermarket shop or buy a newspaper.