Take a deep breath. Did your shoulders go up and your upper chest expand? Believe it or not, you're doing it wrong.
Most of us think we know how to breathe. It's natural. We do it everyday. But most of us also have developed breathing habits that don't support good flute playing.
Lie on your back. Take a deep breath again. Notice anything different? It's impossible to breathe wrong in this position. You can't use your shoulders. Try it again noticing the action of your stomach area.
Underneath your lungs is your diaphragm. It moves down to allow air in and pushes up to force air out. Those of us trained to "hold your stomach in" will have trouble with this motion. When the diaphragm drops, the stomach moves out. Before going to sleep each night, get in touch with this type of breathing and how it feels. Breathing from the shoulders only fills the top half of your lungs. Breathing from the diaphragm allows the entire lung to fill with air.
Test yourself. Blow on your finger. Is the air hot or cold? Cold air comes from the top of the lungs and indicates shallow breathing. Hot air comes from deep inside and indicates proper technique.
Once you've learned to breathe from the diaphragm, work on exhaling using the diaphragm for control. Many of us try to control the air by constricting our throat muscles. This is inefficient and adds tension to the muscles and to the sound you produce.
Now try inhaling again. Was it quiet or noisy? Noisy breathing indicates tension. We sometimes feel we are fighting for air. I personally have noticed that nervousness also leads to noisy breathing. It is also a form of tension.
Blow all your air out. Now open your mouth and let your diaphragm drop. What happened? Air rushed in. Your lungs filled with no "help" from you. It was also silent.
Breathing from the diaphragm can take time and practice to re-learn, but it also gives maximum lung capacity and control. While practicing these techniques, here's one more tip. If your breathing is noisy, try putting your tongue to the roof of you mouth when you inhale. No more noise! I don't have a clue why it works, but it does.
When you play, people want to hear the sound of your flute not your struggle for air. Try these tips. Practice them daily and in a very short time your playing will improve greatly. Your sound depends on your breath. Breathing from the diaphragm is the key to more breath and better control.