Improving Gas Mileage

Hey,

I've got an 04 4.7L 4X4 QC ram 1500. I get about 12mpg on average. I'm pretty sure that's normal, but I was wondering what the best way to improve mpg would be. It already has an knn. also, what flowmasters exhaust is best for this engine? I'm looking more for performance increase opposed to just be obnoxiously loud.

Thanks,
Andrew