Proper installation is the most important way to keep an AC energy efficient. If it is not properly sealed at its borders cool air is constantly escaping, and the compressor is working harder to keep the room at the desired set temperature.
Take advantage of your AC’s timer and programming functions. Set them for appropriate times to reduce continuous usage and reduce energy consumption.
Clean your AC’s filter regularly, a dirty filter restricts air flow and makes the unit work harder than it needs to. Most AC’s will have a check filter feature to inform you when it needs to be cleaned.
Turn off the AC when no one is the room. If you want the room to not be too hot upon returning, leave it running at higher temperature setting to reduce energy usage.