How can I improve my Ford Focus' fuel efficiency?

My Ford Focus seems to be using more gas than it used to. Is there anything I can do to improve its fuel efficiency?

Regular maintenance and tune-ups can greatly improve your fuel efficiency. Make sure to change your oil and spark plugs regularly.

Driving at a consistent speed and avoiding sudden accelerations or decelerations can also help improve your fuel efficiency.

Consider using a fuel additive or switching to a higher quality gasoline to help improve your fuel efficiency.