What's the best way to improve the fuel efficiency of a Ford Focus?

I've noticed that my Ford Focus is using a lot of gas, what are some tips to improve its fuel efficiency?

One way to improve fuel efficiency in a Ford Focus is to regularly check and replace the air filter. A dirty air filter can decrease fuel efficiency by up to 10%.

Another tip is to keep your tires properly inflated. Under-inflated tires can decrease fuel efficiency and also increase wear and tear on the tires.

Avoid excessive idling and maintain a smooth and consistent driving speed to improve fuel efficiency.