effective voice?

Enunciation is key. If what you say makes sense (that is the first problem overcome!) then how it is delivered is the next hurdle in communication. If you are fighting background noise then pitching your voice higher helps. Womens voices always carry further on wireless communications, for instance. Make your mouth move, especially with the vowels. Yes, too many people talk with their mouth almost shut. Make sure you finish a word. Say the T and the D for instance.

before i speak in font of the mass i try to stop all my thoughts and look to the audience the walls chairs everyting in the sorrounding and i say to myself that i have to delever the the things i want to say in a best manner and then say what i want to say in full confidentce and sometimes the subject matter is tough i try to explain them with figures thats all i do