“Keep your voicemail messages short, sweet, and snappy," advises Will Craig, Managing Director of LeaseFetcher. "Don’t try and go into the nitty gritty details of the discussion you’d like to have with them—save that for your actual chat. Alternatively, don’t leave them in the dark about what you want to talk about either. A simple 20-second voicemail letting them know the nature of your query will suffice."
If, on the other hand, your clients work with a number of team members, you might consider hiring a voiceover professional to record your greeting. While a recording with a voice actor is an extra expense, the result often outweighs the cost.

Increase the odds of getting a call back by mentally composing your message before each call. And remember, people hate it when callers state their name and phone number too quickly in voice mail messages – no one wants to listen to a message ten times to comprehend simple information. Begin by saying your name and company (if applicable). Then assume the person you’re calling doesn't have your number, so say your phone number twice. If your name is at all unusual, spell it the first time you say your phone number. Talk slowly like you were writing it down yourself. The second time you say your phone number, you can say it at your normal rate of speech. A gracious phone message is no longer than 30 – 45 seconds. Be pleasant, but also get right to the point. Keep your voice mail message to two points maximum. If you need to share more information, then say you will send an e-mail message with the rest of the details. Leave a specific message. There’s nothing more frustrating than a voice mail that says, “Hi, it’s me. Call when you can!” Even if you’re just calling to say “Hi”, tell them that in your message. End on a high note! You don’t necessarily need to say “Goodbye” at the end of a voice mail, because you didn’t really talk to anyone. Instead, try something like, “Look forward to talking* with you!”
You know that your callers are making inferences about your business and brand. If you want your voicemail recording to leave a positive impression, smile when you record it! Research shows that smiling affects how we speak, and listeners are not only able to identify that people are smiling, but also what the intent is of the smile based on voice intonation alone.