Following these tips of voicemail etiquette and voicemail structure are a sure-fire way to give you a professional edge in your job hunt and throughout your professional career. By having a strong voicemail template to follow you can be sure that when you call your voice(mail) will be heard. I’ve Submitted My Application, Now What? Phone Call, Email, or Meeting? What’s the Best Method to Send My Message? Five Rules of Professional Phone Call Etiquette Is Your Email Address Sending the Right Message?
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.

Pro tip: Only use first names. People of authority call each other by their first name only. Using the contact’s full name or saying Mr./Ms. [last name] can make you seem less confident and important than the person you’re calling.
Reading from a note will help you say what you want without any hiccups or interruptions. Call the person and keep your notes in hand. Once you’re in recording mode, read out from the note to sound as professional as possible.