Do you off-road with yer Jeep? Auto or manual transmission? Does this have full time 4WD? What speed do you set yer cruise to fer highway driving? What do you use to monitor yer gas mileage (Scangauge II, Ultragauge, or smartphone/dongle) with? What gas mileage do you currently git on the highway?
If you can learn how to drive economically using a mileage monitor, you will probably see the biggest increase on yer gas mileage.