I've always found breathing exercises to be very valuable because they help with holding notes and singing higher notes without bottoming out. We did one where you take a deep breath through your nose and then you exhale slowly with an even, constant hissing sound. I'm guessing to point of it was to control breathing. You want a hiss that lasts about five seconds.
Also, another good one was where a section (soprano, tenor, alto) was give a note to hold as long as they could. If a person in that section would drop out or run out of breath, the others had to fill that void by increasing their volume. The increase in volume was enough to replace the missing voice, but subtly not to be obvious. That also helped us compliment each other's voices to achieve a sound of unity since people have different voice types.
Our warm up song was "He Has Done Marvelous Things"
S: He has done marvelous, He has done marveous thiiings. Praise the Lord
A: __ Marvelous, marvelous, marvelous, marvelous thiiings. Praise the Lord
T: Heeeeeeeee haaaassss donnnnne marvelous thiiings. Praise the Lord
They also have CDs that come with vocal exercises. I'm thinking of just playing an exercise off of one of those CDs with my youth choir since I'm not an expert but we do need something if they're going to grow vocally.
