The most important part of vocal training IMHO is breath control. One of my first instructors had me hold a match in front of my mouth the distance of my closed fist away (thumb to mouth) and at first just speak in a loud tone and then holding a note from the piano. The object of the excersize was to keep from blowing out the match while maintaining an acceptable volume. I have seen it done with the match almost next to the mouth. It takes practice. You will have to eventually develop this skill with or without a cd/instructor.
Good luck, Ozlee