Humming
If you're easily tongue-tied, try humming along with the song instead of enunciating the words. The video game doesn't pick up on the fact that you're not exactly singing, and you'll earn points as though you are. Humming is also effective if you're shy to sing in front of a large group.
Start Slowly
As you're learning the game, it's easy to get tripped up by fast, complicated vocals in songs. Instead, choose slow, monotonous songs that are notably easier to sing. Songs that have extended musical interludes are also effective for the beginner. Once you've mastered this style of song, you may be ready for one that's a little more complicated.
Unlock Trophies
You'll be able to earn more points and greater rewards as you unlock more trophies. Not all trophies in "SingStar" are related to your actual performance. You can achieve trophies by adding people to your Friends list (applies only if you're connected to the "SingStar" network), rating the performances of people in your Friends list, excelling at each level of difficulty and uploading your performances to the network.