Arguably the most intimidating factor when leaving a voice mail is the fact that once you leave the message, "in one take," there is no taking it back. That is why, especially in the business world, an overwhelming amount of people revert to email rather than leaving a voice mail message. Especially in a technologically advanced world, email or text messages are now used as a primary form of communication. Although there is a good argument behind opting for the written word over the spoken one, an email can lack the human touch, the emotion and enthusiasm in a voice, that can often times generate a better response. In fact, there is no impact that compares to delivering a clear, concise, professional message through your own unique human voice.
5. On your dial pad, press “1” to listen to your messages, the most recent message should play first.

When you leave a voicemail message, be sure to identify yourself right away. Give your return phone number at the beginning of your message so that other people don't have to listen to you twice. Speak slowly and clearly. It helps to pretend to be writing your number in the air, which will slow you down and help with clarity. Say when you can be reached.
I like to say my phone number very early so the person can hear it again quickly by starting the message over and does not have to listen to your entire message again to hear the number. But do repeat your telephone number at the end of the message at least once and speak very s-l-o-w-l-y so the person can write it down as they listen. If you don't get a response to your first voicemail, don't hesitate to record a similar message once a week for two or three weeks. This sounds a bit excessive, but my experience has been that if there is even the slightest chance of meeting someone now or even in the near future, this kind of message will get their attention.