Five key factors when it comes to having a voice of success include:Your Tone
What does the tone of your voice sound like? Does it reflect confidence? Strength? Assurance? Perhaps your tone reflects fear? Boredom? Immaturity?
Be honest with yourself; do you need to work on your tone? Grab a close friend or co-worker -- ask their honest opinion. It's important to find someone who will give you just that. Listen to what they have to say and take their criticism as constructive to help you develop a voice that will get you where you want to be in life.
When speaking and thinking about the key points you want to emphasize, make sure the inflection of your voice does just that. Inflection alone can change the meaning of a sentence.
Practice, practice, practice. The delivery of your message when training your voice is key. Don't be afraid to rehearse a pitch or a proposal or even just a phone call. You won't always have to do this; just long enough to where a good delivery is natural and you can do it with confidence.
What do you sound like? Have you ever really just listened to your own voice? For example, when you record your outgoing voicemail message what do others hear? A smile? Joy? Authority? Don't be afraid to use a tape recorder as you train your voice. A tape recorder will allow you to hear exactly what others hear.
Similar to tone, but different. The energy in your voice allows people to feel like they are in the room with you. Does your energy make them want to be in a room with you? Put it in check. One thing that I have to watch is the speed at which I speak. I can rattle things off faster than most people can keep up with. I always know when I'm doing this because I often get asked to repeat myself. Breathe, think about what you are going to say and fill it with the right energy for the moment.