Check that there is a karaoke file for the song and download it to your computer.

Look for the lyrics on the internet if you haven't already got them and practise singing along with the singer.

When you can sing the song quite well with the original singer, it is time to try singing it as karaoke.

Enjoy it!

Make sure you have got QuickTime as if not you will hear the music, but you won't be able to see the words and the moving colour.