Good advice in the last post. Change driving habits. It can really make a difference. Don't feel the need to step it up to 80mph on the freeway. Run 60 and get 25% better economy.

Run 40psi in the tires. Make sure your plugs are gapped right. Get those extra bags and boxes of crap out of the truck when you don't need them to lighten the load.

Might not make a lot of difference, but even a little is something.