Just as you need food and regular checkup as human so does these machines too. To avoid having to go through lots of stress and spending your hard earned money, I would provide you with a list of things you should check at least twice in a week.
1) Always check your engine oil to know its quality and level
2) Always check your radiator coolant to make sure it still has its color and lubricating qualities (would point out why coolant should be used instead of water in later posts). DONT check your coolant from the radiator cap too often as this may damage the radiator cap, always check it from your coolant reservoir bottle.
3) Check your brake fluid and make sure it is at its maximum level. (NB: never add more brake oil because for your brake fluid to reduce it can either mean that there is a leak in the system or your brake pads are gettin worn. Another reason not to add more brake fluid is that you dont really know whether the brake fluid in the system can coexist with the new one you are adding).
4) Physically inspect your tyres especially your spare to know its present condition.
5) Check your power steering fluid to make sure it is at the maximum indicated level to avoid your power steering pump from humming and seizing up.
6) Check your wiper blades for flexibility and effectiveness as this may save you during rainfall.
7) Check your battery terminal for crud/ corrosion and clean it up with a bottle of coke.(NB: I wont advice you to remove the battery because that can be catastrophic in some cars so just pour it moderately on d affected terminal)
8) Wash your car with the proper cleansers. Washing your car keeps it clean, shiny and free from corrosion. Remember to clean the interior too while you are at it.
9) Check your wiper washer fluid always, you never know it comes in handy!
10) Always check the condition of your lights to know if they are working, it could save you from dents!