To improve your vehicle's mileage, several strategies can be employed. Maintaining the correct tire pressure is crucial, as underinflated tires can reduce fuel efficiency by up to 10% and lower gas mileage by 0.3% for every 1 psi drop in pressure of all four tires. Driving habits also play a significant role; aggressive driving can lower gas mileage by 33% on the highway and 5% in city streets. Adopting sensible driving practices, such as smooth acceleration, maintaining adequate spacing between vehicles, and avoiding unnecessary braking and acceleration, can improve fuel economy by 5-33%. Using cruise control on the highway helps maintain a constant speed, reducing the need for braking and accelerating, which can save gas. Observing the speed limit is also important, as gas mileage decreases rapidly at speeds above 50 mph, with each 5 mph over 50 mph costing an additional $0.25 per gallon. Regular car maintenance is essential; keeping your engine properly tuned can improve gas mileage by an average of 4%, and using the recommended grade of motor oil can improve it by 1 to 2%. Avoiding excessive idling is another key tip, as idling can use a quarter to a half gallon of fuel per hour. Turning off your engine when parked and avoiding drive-thru services can also help. Additionally, removing excess weight from your vehicle can improve fuel economy, with an extra 100 pounds reducing MPG by up to 2%. Keeping your vehicle clean and free of aerodynamic drag by washing and waxing it regularly can also improve fuel efficiency. Finally, planning your trips efficiently, such as combining errands and using GPS to optimize routes, can minimize the distance driven and save fuel, money, and time.