Start in a lower key
Our muscles, including our vocal cords are relatively more relaxed when singing lower notes than when singing higher notes. So start off gently in a lower key and work upwards to the higher ones.
Begin with a lip trill
Lip trilling is where we make a brbrbrbrbrbr sound, like blowing bubbles under water. It can be done with and without sound and is very gentle on the vocal cords because some of the air forced out of the lungs is being used to vibrate the lips rather than the cords.
The lips should be relaxed, not tensed. If you find it difficult to relax your lips push your fingers gently into your cheeks either side of your mouth and make the brbrbrbrbrbr sound again. It should be easier.
Try some short scales
A scale is a run of consecutive notes. Think Julie Andrews in The Sound of Music singing do-re-mi-fa-so-la-ti-do.
A short range of notes travelling up and down the scale might be do-re-mi-fa-so-fa-mi-re-do.
Use a vowel sound (like ah, oo or ee) to run up and down a few short scales. Gradually extend to the full scale to stretch your voice.
Drink plenty of water
Drinking water is important when singing but also generally. Making sure we keep well-hydrated is important for our voice and our over all health.
Stop if it hurts
Don’t over-do it. If your voice feels strained stop practising. Also if you have a sore throat you should rest your voice.
Try to fit a few minutes of warm-up practice into every day to strengthen and improve your voice.
*** The BBC ‘Sing’ website is a great resource for choirs.