Get the right tone.
Question: Do you want to return a message left by a guy who sounds slightly harried, kind of bored, or mildly anti-social? Of course not! Try to keep your message lively and friendly. People like lively and friendly. People want to call lively and friendly.

Don’t ramble!
Checking voice mail is the modern equivalent of tossing the bedpan’s contents out the window. Necessary but not fun. So make sure you spare the listener any more anguish than is absolutely necessary by being quick and to the point. BUT that doesn’t mean you should be terse and cold. Short and clear yet lively and friendly. Short and clear yet lively and friendly. Lastly, short and clear yet lively and friendly.

Speak your telephone number s-l-o-w-l-y.
Not everyone is as familiar with your number as you are.

Leave your number in the beginning and end.
This spares the person from having to listen to the entire message if she didn’t get the number during the first listen.

Don’t assume that your flawless voice mail will inspire a callback.
Set a time to call back (make sure, though, that you give the person an ample opportunity to call you).