How do you improve the gas mileage on a 2000 Nissan Frontier?

Drive slower and don't ever do jack-rabbit starts from a stop. Reducing your freeway speeds to below 60 MPH greatly reduces your fuel comsumption. Avoid constant surging of speeds going slow, speeding up to the rear bumper of the car in front, then slamming on the brakes, then speeding up again. Always maintain as constant a speed as you can. You see tour buses do this, and they hit most lights green.