What is the best way to maintain an Audi A2's fuel efficiency?

I have noticed a decrease in my Audi A2's fuel efficiency and I'm not sure how to address it. What are some key steps I can take to maintain or improve my car's fuel efficiency?

Make sure to regularly check and replace your air filter. A dirty air filter can reduce fuel efficiency, so it's important to keep it clean.

Try to avoid idling your car for long periods of time. This can waste fuel and decrease efficiency. If you know you'll be stopped for more than a minute, turn off your engine.

Keep your tires properly inflated and aligned. This can greatly affect your car's fuel efficiency.