How to get a louder sound from a high school tuba section?

[Boomerbryce]

Breath Control.

Try this excercise. Breathe in for X seconds, hold for X seconds, and blow out for X seconds.
This got not only a better sound, but louder when I needed it/

Start with X at 10 and try to work it up to 25.

If you can get it to 30 amazing,

Try it
Boomerbryce