Buy used this will save you in depreciation, as generally as soon as a new car it will lose up to 30% of its value right there. More care needs to be taken on due diligence on the car, as if you buy a lemon then you will not be saving any money, and just getting heart ache.
      Buy the right car focus on a car which is reliable and fuel efficient, this one choice can save you thousands, and forget about buying a new car, buy used and you will lose much less in depreciation in the car. To give you an example of what you cold save if you drive a vehicle for 100,000 miles and choose a car which gets 15 mpg vs. a car which gets 25 mpg and with gas at $3 you save $6,000. Getting a car which is reliable will save you the hassle of having to get your car repaired, which can be very expensive as well as inconvenient
      Carpool can be a great way to save money, if there is someone who lives nearby who works in the same area as you. Fuel costs are halved as well as wear and tear on your car, and with gas prices set to increase and stay high for the foreseeable future this is a quick way to become less dependant on oil.
      Reduce your speed as the optimal speed for fuel consumption is generally 50 to 60 miles an hour, there is a reason that trucks go at this speed, and it is not just to annoy other drivers. The actual time saved is usually only 5 or 10 of the journey anyway, unless you have the good fortune to be mostly high way driving.
      Downsize to only one car this can save you with insurance and maintenance costs, though does require more management and planning, potentially it could work better in combination with car pooling.
      Use public transportation if you can ditch the car completely then you will save a huge amount of money, no more fuel costs, insurance as well as the cost of the car. Though for some people it is not an option as they enjoy just owning a car so getting value beyond just the utility of getting from A to B. Also unfortunately this is only possible when you have a good public transportation system, but it can be feasible. Generally public transport will end up being cheaper especially once you consider the total running cost of your car. For times when you do need a car you can always rent a car or there are some city based car rental schemes where cars are dotted around the place and you can pick up the local one for a set fee per day.