One of the exercises, useful for any singer is bellowing. Lie down or sit in a comfortable position and relax completely.
Start evenly and quietly make a sound "m-m-m", imagining that your head is tied to the ceiling by a rope. Make the sound more tense, and then change the tone and continue to "hum". Do this exercise for about three minutes, then move on to the next, which gives a good load on the ligaments.
Enter the air into the lungs and then say the sound set: "VF-VF-VF". Say the sounds together, not tearing them down between himself and rocking music. At first the sound may be unstable and uneven, but with time you have to achieve uniformity, breathing is always the same amount of air.
After three minutes, go to another exercise – try to roar at a different volume. Growling good massages and develops ligaments, preparing them for full-fledged singing.
And of course, as a warm up you can use the musical octave, singing separate syllables on the notes "a – o-u-I", "mi-me-mA-mo-mu", and others. For a start drink every syllable sharply and abruptly (in stacatto), and then try to make the transitions between the sounds smoother (Legato). These simple exercises will help you to prepare the voice for singing, without undue harmful effects on the vocal cords.