How can I improve my Volkswagen Golf's gas mileage?

I noticed that my Volkswagen Golf's gas mileage is not as good as it used to be. Can anyone provide any tips or suggestions to help improve it?

Regularly check and replace your air filter to ensure optimal performance. This can significantly improve your gas mileage.

Avoid accelerating too quickly and braking too hard. These driving habits can significantly decrease your gas mileage.

Make sure your tires are properly inflated. Underinflated tires can decrease gas mileage by up to 0.3% for every 1 PSI drop.