Singing is physical and acoustical. There are a lot of preparations to do to become a good singer. It takes many years of training and studies for you to sing well. You don't have to worry though. I have some tips and suggestions that you can do to prepare yourself for your choral subject. First is your posture. Your head must be balanced over your shoulders, hips and feet. It means you must stand straight and should not slouch. Your chin must be a little bit lower. Second is your breathing. Exercising your breathing is one point for you produce a clear and full volume of sound. Every time you inhale, your front abdomen must expand or move forward and when you exhale it should move back in. Open your mouth and drop your lower jaw. Relax your lips, tongue and neck. Third, try to find a recording to use as a model for vocalization. This will help you exercise your vocal cords. If you cannot find any recording for vocalization, I suggest that you bring recorder to your voice lesson so you can record the vocalization performed by your teacher and practice at home.