[fredjacksonsan]

Proper tire pressure. Light on the throttle under acceleration, and let off the gas early and coast to a stop @ lights and stop signs, rather than braking. Try synthetic oil, that's usually good for 1-2mpg. You could also try synthetic in the transfer case and differentials, and if you have manual transmission, in the transmission. Make sure you keep your air filter clean and your spark plugs get replaced on or before schedule.