Tips to improve fuel economy, take care of the tires. Check the tire pressure regularly- if you can, do it every Sunday or whenever you wash your car. Every specialised internet site or magazine will tell you this because it really works. If the tire pressure is low it increases the rolling resistance of the rubber and you pay more for the gas. Check the pressure of the tires to be the same as the one recommended by the maker.
Use low roll resistance tires if you can. Maybe you have not heard of it but many tire makers have such models (BMW, Pirelli, Michelin, Dunlop). Using this type of tires means less resistance when the tire rolls on the contact surface of the road. This thing takes some load off the engine and it translates in a better fuel mileage. A 0.5 l/ 100 km drop has been noted when used with alloy rims, just by modifying the tire profile.