How to improve the fuel efficiency of my Volkswagen Polo?

I have a Volkswagen Polo and I'm looking for ways to save on gas. Any tips for improving the fuel efficiency of my car?

Regularly checking and replacing your air filter can improve your car's fuel efficiency by up to 10%. I recommend doing this every 12,000 miles.

Keep your tires properly inflated. Underinflated tires can decrease fuel efficiency by up to 3%. Check your tire pressure at least once a month.

Avoid aggressive driving and speeding. Not only is it unsafe, but it can also decrease fuel efficiency by up to 30% at highway speeds.