What three changes would you make to a 1996 Dodge Ram 1500 (5.9L) to improve mileage?

Bambi B questioned:

The aforementioned car gets about 10-11 mpg. I’ve seen ads for normal chips, air filters, fuel logic gizmos – all gifted increased fuel efficiency. What facility, and what doesn’t? What would your recommendation be for the top three changes to boost mileage?