How can I maintain the gas mileage of my Nissan Qashqai?

I have noticed that the gas mileage on my Nissan Qashqai has been decreasing lately. What are some tips for maintaining optimal gas mileage?

Regularly check and replace your air filter. A dirty air filter can decrease gas mileage by up to 20%.

Avoid idling for long periods of time. Idling for just 10 minutes can use up to half a gallon of gas.

Make sure your tires are properly inflated. Low tire pressure can decrease gas mileage by 0.2% for every 1 psi decrease.