With a manual gearbox, choose the highest possible gear for your speed. If your car is equipped with a gear change indicator, adopt the recommended gear speed whenever possible. An engine running at low speed consumes less fuel even if you have the impression that it has to work harder to move forwards.
With a clutchless or automatic gearbox, an automatic gear change function adapts the gear speed to the driver's style. Use this function wherever possible and drive smoothly. If you use the accelerator pedal in moderation, the automatic function will optimise fuel consumption by selecting the most appropriate gear for your speed.