1. Choose a song that you know well and are comfortable with. It will be easier to maintain your pitch and rhythm if you know the melody and lyrics inside and out.
2. Use a metronome or other device to help you stay in time. When you don't have music to follow along with, it can be easy to get off track, so a metronome can help you keep a steady tempo.
3. Visualize the sheet music when you are singing. You will be able to remember melodies and lyrics when you use this method if you are familiar with musical notations. If music appears in your thoughts, you'll probably be inspired to hum along.
4. Record yourself and listen back to your performance. This can help you identify areas where you need to improve, such as pitch, rhythm, or tone.
5. Practice, practice, practice! The more you sing without music, the better you'll get at it.