1-Slow down
Slowing down may save you some gas ,your car fuel consumption increases exponentially with car speed , don not try drive at speed more than 90 km/hour
2-check car tire pressure
3-check air filter
Don't let dust get into your engine it will cause damage to your engine and it will consume more gas as the burning operation is not efficient ,choose a good reliable air filter for your car and keep it clean all the time
4-don't use AC
If the temperature is not extremely high then turn off your AC it will save you up to 10% of gas
5-keep your car light
Try to remove any unnecessary weight from your car keep it as light as possible
6-choose small car
Small cars burn less fuel it is that simple!!
7-warming car
Don't warm car too much , new cars don't need that time ,one minute is enough
8-fuel filter
Keep your fuel filter also clean to increase efficiency of your car
9-efficent car
when buying car choose fuel efficient cars, it is that simple look on internet for that type of car and you will find a lot.(look for Toyota or a BMW like BMW 335d )
10-don't drive
If the distance is not that long don't drive ,instead walk or ride a bicycle, it is good for your health and to your pocket too :)