What's the best way to improve gas mileage on a Ford Transit Custom?

I've noticed that my Ford Transit Custom is not getting the gas mileage that I was expecting. Any tips for improving its fuel efficiency?

It's important to make sure your tires are properly inflated, as underinflated tires can decrease gas mileage. Also, try to avoid idling for long periods of time and use cruise control when possible to maintain a steady speed.

You may also want to consider using a fuel additive or switching to a synthetic oil for your engine. These can help improve fuel efficiency. It's also a good idea to regularly tune-up your vehicle and keep it well-maintained.