One should be sure that they are aware of who his or her audience is. That said, he or she should also be aware of the overall feeling of the audience. If a presentation is being given on a controversial subject, the audience will (most likely) include proponents from both sides. Therefore, the speaker must do everything possible to insure that he or she is not being offensive to either side. That said, one does not need to change his or her own prospectives in order to satisfy an audience--just be respectful.
As for how to control the voice and confidence, this is all about relaxation. As a student, I had a very hard time speaking in front of people. My hands would shake and my presentation would be filled with vocal pauses ("ums" and useless words). I had to learn to control my insecurities and fears. It was really only through forcing myself to calm down that allowed me to speak confidently in front of others.