Voicemail messages complete your professional image. Whether you are using your cell phone as a mobile office or desire a unified sound for all of your employees, voicemail greetings recorded by a professional voice over talent provide the missing element.
To create a greater sense of authority, and that you are somebody important, list the name of a person and company who you've worked with before, especially if that person and company is a direct competitor of the person you are calling. Nothing grabs the interest of the person you are calling faster than hearing the name of their main competitor.

This is ‘How to Leave a Professional Voicemail Etiquette 101’: Always let the person know how to reach you.
The above section details types of phrasing to avoid; however, it doesn’t detail what users should NOT say on their greeting. Though this is a bit loaded, as there are hundreds of combinations of things one shouldn’t say, there are some key components users should ALWAYS avoid. a. Forget About Slang: You should strive to be as professional and welcoming as possible in your greeting. While this may steer you towards using slang, in an attempt to make callers comfortable, it’ll most likely work against you. As a professional, your demeanor, tone, and speech should be clear cut and well articulated. Using slang undercuts this and works against you. b. Don’t Even Think About Profanity: This is a no-brainer. Never, under any circumstances, curse in your greeting EVER! c. Keep Your Sentences Clean, Don’t Ramble: Introduce yourself and give your caller specific direction. Avoid long diatribes detailing tangent thoughts. Keep it simple and quick. d. Always Return Your Calls: It’s important for callers to feel they are valued. Nothing dissolves this quicker than a greeting that doesn’t stress this. For example, “I’ll call you when I can,” “If I don’t return your call, please call back”—these phrases are terrible and completely destroy any good will you may have with a caller.