How can I improve the gas mileage on my Vauxhall Insignia?

I have been noticing that my Vauxhall Insignia's gas mileage has been decreasing over the past few weeks. What could be causing this and how can I improve it?

Firstly, make sure that your tires are properly inflated and aligned. Under-inflated tires can greatly decrease your gas mileage.

Consider changing your air filter. A dirty air filter can restrict air flow and decrease your engine's efficiency.

Try to reduce your speed while driving on highways or long stretches of road. Increasing your speed can significantly decrease your gas mileage.