What is the best way to improve my Ford S-Max's fuel efficiency?

I've noticed that my Ford S-Max's fuel efficiency has been decreasing lately. Is there any way I can improve it without spending a lot of money on modifications?

One of the best ways to improve fuel efficiency is to make sure your tires are properly inflated. Under-inflated tires can decrease fuel efficiency by up to 3%.

Avoid aggressive driving and excessive idling, as these can greatly decrease your fuel efficiency. Instead, drive at a consistent speed and plan your route to avoid traffic if possible.

Regular tune-ups and maintenance can also improve fuel efficiency. Make sure to follow your vehicle's recommended maintenance schedule and keep up with oil changes, air filter replacements, and other routine tasks.