Be sure to check your tire pressure regularly, and keep it at the recommended level. This is usually found in your owner's manual, the door post or your glove compartment.
Remember that over inflation of your tires is just as dangerous as under inflation. This can cause any of the following to occur...
Uneven tread wear
Weaken your tires
Imact gas usage
Remember to rotate and balance your tires as recommended by your car's manufacturer.