The answer to 'how to fix AC' is to start by checking the air filter and cleaning or replacing it if it's dirty. Next, inspect the outdoor unit and clear away any debris or vegetation around it. You can also use a garden hose to gently clean the coils on the outdoor unit. If your AC is still not cooling properly, you may need to have a professional HVAC technician inspect the system for any refrigerant leaks, electrical issues, or other problems.
Regular maintenance is key to keeping your AC running efficiently. It's recommended to have your system serviced by a professional HVAC technician at least once a year, typically in the spring before the hot summer months. They can perform a full inspection, clean the system, and ensure everything is working properly.