Funny, the majority of us have a phone on us more hours of the day than not, but actually we’re harder to talk to than ever. On personal calls, and especially business calls, you’re much more likely to reach voicemail than the actual person you’re hoping to engage in conversation.
Now, this might seem like I'm reneging on what I just said, but you can easily reconcile this point with the one above. While you should keep your tone conversational, you can't get carried away.

It's never been more important for salespeople to be good at leaving voicemails. Not only that, but voicemail can — and should — be measured, coached, and improved. First, let's review general voicemail etiquette. Keep your greeting up-to-date. Let callers know when they can anticipate a response. Share your name and company affiliation. State the intention of your message. Include your contact information at the beginning and end of the message. Be concise. Share your availability.
How do I record my Voicemail Greeting over the Phone? Dial the Voicemail Access extension 899 (default) Enter password followed by #. Press 0 for Mailbox Options. See Also How do I record personal greetings for Voicemail Options.