What is the best way to maintain the fuel efficiency of my Toyota Prius?

I recently purchased a Toyota Prius and I'm worried about maintaining its fuel efficiency in the long run. What can I do to make sure my Prius continues to save me money on gas?

Regularly check and replace your air filter to ensure proper air flow into the engine.

Consider using a fuel additive to improve fuel economy.

Make sure your tires are properly inflated to reduce rolling resistance and improve gas mileage.