1. Limit Background Noise. If you’re recording your greeting from the back of a New York City cab with the windows down, it’s gonna be pretty obvious to your callers.
Remember that we can hear a smile in another person's voice, just as we can discern whether that individual is completely present and focused. Smart phones have the ability to record. Smart people take advantage of this tool and record themselves before leaving a message. And yes, it takes time. Precious time.

Friends and colleagues speak to each using first names only. So do people of authority. They do not call each other and leave voicemail messages asking for Mister, Miss, or Mrs. Therefore, when you call a person you want to do business with and you leave a voicemail message, refer to them by their first name only. Don't say mister, miss, or misses. Don't say their last name. Begin your voicemail message by saying only "hi/hello" followed by the person's first name. Or, you can even forget the "hi/hello" and just say the person's first name. That is how you show confidence and authority and separate yourself from weak salespeople.
A word of warning: These greetings will not do you any favors if you're in the midst of a job hunt or work in a conservative industry. Always remember your target personas. If there's a chance they won't appreciate your sense of humor, opt for a straightforward greeting instead.