53 MPG is not bad at all. Here are some tips that helped me improve my gas mileage from 43.3 MPG to 62.1 MPG.

1. Don't go over 65 MPH on the freeway. The fuel efficiency drops drastically between 65 and 70 MPH. You will get the best gas mileage at 55 - 59 MPH.
2. USE CRUISE CONTROL on the freeway. You WILL see an immediate result with this.
3. USE CRUISE CONTROL in the city as much as you can. You can get on cruise control at 25 MPH or above.
4. When you accelerate, don't slam on the gas. Go easy and gradual. If you are at 25 MPH or above, you can use the "up" and "down" shift on cruise control to accelerate or decelerate.
5. If you see a red light ahead of you or when you KNOW you'll have to stop soon, let go of gas and start coasting. The less you have to rely on the brake to stop, the better gas mileage you get.
6. You won't get as good gas mileage when your outside temperature is below 40 F or above 90 F. The idea temperature is between 50-70 F.

On your next trip, try going steady at 57 MPH with cruise control on the freeway while having your "Trip Information" on your screen and see what it tells you. I think it will raise your eyebrows. Good luck