keep your car well maintained, keep your tires inflated to the proper psi, try not to do jack rabbits starts, avoid rush hour traffic, and keep your speed down that's the number 1 reason that people lose mpg - speeding!
I really watch the speed when im being cautious about the gas I use. I dont see how you can get by with not going anywhere a few days a week. We are so busy here that it seems like were always on the move.
With all the people with lead feet here on the highway,it's hard to not want to go past the 70 mph that I like to drive at. So besides saving gas it saves me from going to fast also.
Speed is the number one killer of high mpg. Every rpm that's over the lowest rpm that will keep your vehicle moving in your highest gear steals extra fuel ... typically that's your best mpg.