DRAFTING

Drafting

 Drafting has given me some excellent mileage when I used to commute long distance a long time ago. Obviously, it requires a bit of skill and it's not exactly recommended, since you should pay attention to the road and we all know, most people who read this just don't. However it is probably one of the best "secret" fuel saving tips I can give you.
This technique is frequently used by race car drivers to gain speed and truck convoys to save fuel.
Every car has a certain amount of drag (or wind resistance). This drag, the rolling resistance of your tires and the friction in your engine are the three main causes of reduced efficiency. A car moving through the air causes the air to split around the car and turbulence behind the car. If you drive your car into another cars slipstream, both cars will save fuel (less turbulence). The following car saves the most gasoline.
Now remember, I am not advocating to tailgate. However, you can try to find a large truck (more turbulence and a longer slipstream tail) and slip in there. Now you can still keep some distance (unlike the NASCAR driver) and still save gas.
However, many people cannot regulate their speed without braking (see above). In this case you are probably better off just keeping your distance and not braking.