Tire Pressure light on my car won't turn off!

Along with all the other good advice above, check the tires first thing in the morning, before you drive anywhere. If you don’t have an air compressor (most don’t), keep track of how many psi each tire needs, then go to a nearby gas station and add that many psi to the appropriate tire. So if the right front tire is 5 psi low first thing in the morning, add enough air to increase the reading at the gas station by 5 psi. Then check it again next morning.