1) Try checking mileage with and without cruise control.
I have found that driving on a long trip in moderately hilly country without cruise control is better for fuel mileage. Allow the car to slow a little going up hills rather than insisting on maintaining a set speed as a cruise control will do.
2) Buy a new car with a standard transmission to save about $900. As a bonus, the acceleration and fuel mileage will be better. Shifting gears in the city is not difficult.
3) Slow earlier for anticipated stops. Red lights can often be anticipated on a known route. This not only saves fuel but brake linings too.