Decent audio quality.
The system should include either a decent set of built-in speakers or an audio output to connect it to your home stereo's speakers.
Multiple music sources.
Look for a machine that can stream music from a variety of devices, such as an included CD+G player, a home CD or DVD player, an MP3 player or a smartphone.
A display screen for lyrics.
Some karaoke machines come with a built-in display, while others hook up to a TV set or tablet computer.
Machines designed for home use should be basically plug-and-play.
It should be easy to adjust the volume of your voice and the backing tracks, as well as switch between different musical inputs.
Karaoke parties can get a bit rowdy, so look for a machine that will stand up to rough handling.
Even a short warranty of one to three months will protect you in case you end up with a lemon.