Do you speak a second language and serve customers in an area that primarily uses a language other than English? Make it known that you speak both languages. Start the voicemail with the most dominant language spoken in your market followed by the same message spoken in the secondary language:
Think through what you are going to say before you place the call. When men hear the beep, they often freeze up and forget what they wanted to say. If you want to be the go-to guy at work, then you have to exhibit competence on all levels. Don’t spoil your confident image by hemming and hawing and filling your messages with “uhhhhs,” and “ummmms.” If it’s a really important call, consider writing out what you want to say beforehand. If the person picks up, great, you now have some notes to remember what you wanted to talk about. If they don’t answer, you can leave a clear and concise message.

Hello you are talking to a machine; I am capable of receiving messages. My owner (your name here) does not need siding windows or a hot tub, and her carpets are clean. She gives to charity through the office and she doesn’t need her picture taken if your still with me please leave a message and she will get back with you.
I think it’s a sad reality that most organizations use a telephone system to screen and triage phone calls before transferring the call to the appropriate person – forcing an electronic interaction that isn’t always customer friendly.