What state are you located in? If you're being forced to use a winter blended fuel that is also contaminated with ethanol, the gas mileage your vehicle is delivering might be perfectly normal.
To improve fuel economy, make sure the spark plugs are in good shape, the air filter is clean and flowing freely, the tires are inflated properly, the vehicle is in alignment, you don't press on the accelerator very hard and you are using a top shelf synthetic oil in the engine and synthetic transmission fluid, like AMSOIL.