Of course you need your voice to practice your singing but there are other tools which will help to make your training sessions more productive:
Keyboard: Just about any new or used electronic keyboard works. A piano is fine, too, as long as it’s in tune. You don’t have to know how to play the piano to sing, but if you want to get a better understanding of what keyboards and musical notation are all about, pick up a copy of Piano For Dummies, 2nd Edition, by Blake Neely (Wiley).
Recording device: A recording device is super useful because all you have to do is record the music once and then play it back during your practice time.
Recording your practice sessions is a great way to monitor your progress, too. Record yourself singing through the exercises, and then rewind to hear whether you were right on pitch or whether a vowel really was precise.
If you want a sound that’s a bit more sophisticated, use a digital recorder (such as an iPod or recording application on your phone designed for recording music or singing) — the sound quality is much better than with tape recorders. The sound of your voice played back on a quality digital recorder is closer to what you actually sound like.
Pitch pipe: The leader of the choir or barbershop quartet whips this gizmo out of his pocket and blows into it to sound the starting pitch. If you don’t have a keyboard or a recording with your exercises handy, you can get a pitch pipe and play your starting pitch. You can also play a pitch occasionally to see whether you’re still on target.
Metronome: This gadget monitors speed and maintains rhythm — not like a radar gun, but more like a ticking sound that encourages you to stay at the same speed or tempo when you practice. Most songs have a tempo marking at the beginning. You can set your metronome to this speed to experience the tempo that the composer intended.
If you can’t locate a metronome, look at the clock. The second hand on the clock is ticking 60 beats per minute. You can practice your song or vocal exercise while keeping a steady pace with the ticking of the clock.
Mirror: Mirrors are so helpful for practicing. By watching yourself in the mirror, you become much more aware of how you move your body as you sing.
Music and pencil: As you listen back over the recording, take notes in your practice journal or on your music. Seeing the notes from your last practice session helps you remember your goals.