It's summer, which means a lot of people in the country are going to be running their air conditioner. It also means that a lot of air conditioners are going to stop working properly, because that's what happens when you use something. Eventually it stops working properly and needs to be fixed. Sometimes, whatever needs to be fixed is something you can take care of, and of course sometimes you'll need to call in some air conditioning services to repair your unit.
In the first place, it's important to know that your air conditioner (probably) isn't designed to turn your house into a meat locker. Most air conditioning units are designed to drop the internal temperature of the house about 20 degrees below the outside weather. If the air conditioner keeps running and running but your house isn't cooling off to the set temperature (but still seems to be cooling the house) this is possibly what's causing the issue. You'll want to adjust your air conditioner up a few degrees, or switch it off for a little while, so that the unit isn't constantly running. They aren't supposed to run constantly, and being forced to run constantly can cause expensive break downs.
Once the sun goes down you can generally turn your unit down a few degrees and get the house a little cooler. You can even have a programmable thermostat installed and set it so the temperature automatically drops at night, which will save you from having to remember to do it all the time.
You also should know when the last time you replaced your air filter was. A clogged air filter can mean the whole system is struggling to draw in air, and it puts more stress on your unit. You may have heard that you need to do this once a year, but in truth, that varies wildly. If you live in a place that does not have great air quality, or you have pets, you could need to change a lot more frequently like that. If you're not sure how often you'll need to change it, just try to check in on it every once in a while, and change it when it gets too clogged.
Some thermostats will actually let you know when the filter needs to be changed, too, so if you have that variety you can just keep an extra filter for your a/c on hand.
Some problems are bigger than that, and you may need to have your unit serviced this summer, but hopefully you feel at least a little bit more confident about where to start with diagnosing air conditioning issues.