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.
Creating a professional voicemail greeting isn’t complicated, but you need to keep a few things in mind to ensure success. The following tips will help: Be friendly and welcoming - let your company's personality shine!; Have a clear voice, speak at a slow to moderate pace, minimize background noise; Ensure the greeting is human and approachable; Keep the greeting short and informative; Ensure the greeting doesn’t sound robotic or unnatural; Show your gratitude for the call by saying thank you; Manage expectations by clearly stating when the client can expect a callback.

When opening your voicemail, start with a professional or generic greeting like, “Hello” or “Good Morning”. Be sure to clearly state your name, who you are/where you’re from, and (where applicable) how you got their contact information.
State your number right after your name. Many people wait until the very end of the message to state their number. This will irritate the receiver of your message because if he doesn’t get it down, he then has to sit through the whole damn message again to hear it repeated.