It's worth repeating: the number one rule in taking care of your car is to read the owner's manual. The instructions in that manual are specific to your car, and in most cases, the picture diagrams will be very helpful in guiding basic maintenance work on your car. Below, however, are four simple jobs you can do no matter what type of car you have:
1. Clean your car: Cleaning may not necessarily help your car run better (though it might), but it will give you car a well-maintained appearance. Wash the car regularly, including hosing off the undercarriage, and wax it twice a year to make it shine and protect its paint job. In addition, remember to clean the interior of your car; remove as much clutter as possible and vacuum the cloth areas. You can wipe plastic, vinyl, and leather areas with a damp cloth if you don't want to purchase special cleaner.
2. Inspect your tires: First, buy a tire gauge (less than $10) and check the air pressure in your tires. The pressure should match the suggested pressure printed on the doorjamb of the car. Second, eyeball your tires to examine the tread. Check for bald spots and do the Lincoln Penny test--put Lincoln's head down into a tread, and if you can see the top of his head over the tread, you need a new tire.
3. Check your alignment: One day, while you're driving on a long, straight, flat, and deserted road, pull your hands off the steering wheel. If your car veers one way or the other, the alignment is likely off, and you should have it checked.
4. Play with stuff: It sounds silly, but get in the habit of turning dials and pushing buttons in your car. Do the air conditioner, heater, and defroster all seem to be working? What about the automatic locks and windows and the overhead lights?
Finally, most drivers have learned that it pays to use your senses. Are you feeling any odd vibrations as you drive? Do you notice any strange smells when you get out of the car each night? Do the brakes make any strange noises? The quicker you spot a problem, the easier it is to avoid a major problem.