Rotate your tires, front to rear, at the most every 10,000 kms. This is especially important on front wheel drive vehicles. The tires on the front will wear faster than the rears, and if you don't equalize that wear you will be buying 2 tires very prematurely.
Always keep your tire pressure up to specs and even all the way around. You should check this at least once a month.
On the side of the tire you will find the max pressure rating. This is what you should keep you pressure set at. If the ride seems too harsh then drop them all down 2 or 3 psi. No more, that is, as long as you want to get maximum wear out of your tires.
You will also get better fuel economy out of your vehicle by keeping the tires inflated to the maximum pressure rating.
If you notice your car pulling left or right, a slight vibration at highway speed or a thumping sensation at low speed, get your vehicle into a professional tire center and have the tires checked. It may very well save you from wearing out a tire prematurely or even from a dangerous blowout.
By following these simple tips you will get the most wear and safety out of your tires, and better fuel mileage in the bargain.