Better MPG for '12 Ram 1500 ????

I have a '12 Ram 1500 5.7L HEMI.
I have installed a K&N air filter and am looking for other things I possibly can add to increase HP/MPG (mostly MPG). They probably have those cold air intakes but do those really do much?
Would my next step be looking into different exhaust? Or what else?

thanks guys

YOU NEED SOME TRUCK NUTS:sunglasse