Changing the engine oil every 3,000 miles or so is standard car care.
Your manual will come with a recommendation. You can go with that or have the air filter checked with every other oil change.
Properly inflated tires increase fuel efficiency, reduce wear, and increase safety. Tires should be checked every other month.
This is a highly neglected form of car care. The fluids for power steering, transmission, brakes, and radiator coolant all play large roles in the healthy functioning of your car. Check your fluid levels every month.