The more personal and specific the question, the more likely it'll get a response. Think about it this way. If you start to have chest pains on a busy city street, and you cry out, "Somebody call 911!" you might get help … but you might not. However, if you were to point at one specific person and shout, "Would you please call 911 for me?" it's almost a certainty that the stranger you selected would grab their phone and dial.
The length of your voicemail plays a big role in its efficacy. Try to keep the length of your voicemail between 15- 30 seconds. Anything more and you will be rambling, anything less, and you’re probably not checking one of the three boxes above as effectively as you need to.

Remember, your prospects (and you too, if you're honest) care mainly about themselves. In other words, your sales voicemails will be much more successful if the benefit to the prospect is clearly stated.
Not only do you sound more articulate and confident when you're not rushing to the finish line, but you also sound more authentic. Speaking in a rush suggests you've been dialing all day and need to be as efficient as possible. Yet if you're making three calls rather than 30, you're probably going to sound far more deliberate. A slow finish tells the buyer they're not just another name on a list.