Voicemails don’t necessarily have to be monotonous or extremely jazzy or funky. What you’re looking for is a balance between the two. Whenever I call someone and their voicemail greeting is playing, it tells me a lot about who they are, as a person. Which is why, you’ve got to put a little bit of “you” when it comes to voicemail. And the best part about all of this is, since you couldn’t come to the phone, at least the callers are having a good time listening to the message.
Make the last thing you say be your phone number. This ensures it's clearly visible on voicemail dictation, and makes it easy for prospects to call back. Avoid phrases like "Call me back when you get this," which can sound pushy. And, finally, tell them you'll follow up with an email. This gives the prospect two ways to return your call, which certainly can't hurt.

As I said, I use a “3 strikes, you’re out” rule. You may find that 4, 5, 10 or 20 works best for you, but for me, it’s 3.
If you can, try to keep your message 20 to 30 seconds long — max. This is the sweet spot for sharing just enough information without going overboard, potentially getting cut off by the recipient’s voice mailbox system, or having the listener hang up early because your message was simply too long. Speak clearly, avoid rambling, and get straight to the point.