Breathing

It's important to breathe in deeply in order to project your voice and to have power and resonance. You won't be taking in more air, but you will be breathing into the lower portion of the lungs instead of into the upper portion of the chest.

Exercise 1 - Put your hand on your upper chest. Breathe so that this part of the chest moves out when you breathe in. As you breathe out, let out an "Aaahhh" with the breath. Now put your hand in the middle of your chest and breath into this area, and as you release your breath say "Aaahhh." Now put your hand on your solar plexus and do the same thing. Lastly put your hand
on your stomach and as you say "Aaahhh" as you let the breathe out notice how much stronger your voice is when you speak from here, and notice how much more resonant your voice is.
If this isn't easy for you try holding your hands above your head while you do this. As a last resort you can lie on the floor and practice there so you know how it feels, before you practice standing up.
While you do this remember to keep your shoulders slid back and your back straight.