Remember that the speed of your words can negatively impact your message as well. "If you have to rush to get a message into the amount of time allotted for a voicemail message, you’re saying too much," DeCesare advises. "Say less and slow down. You want them to feel that talking to you will make their lives less stressful. If you're frantic and mumbling on the phone, it gives them a foreshadowing of what it will be like to work with you."
This script comes from Donato Diorio and it's quite simple and to the point. But it still does a great job of highlighting prospect benefits and the follow-up plan.

Once you finish your voicemail message, you can end on a note of gratitude and express thanks or that you realize the recipient of the message us busy, so you’d appreciate a return call. Whichever way you choose, make certain that the tone of your message is upbeat. A business voicemail greeting sees each call as their chance to engage with their clients or vendors. Hello, you’ve reached the office of Lydecker and Lydecker. We are currently unavailable to answer your call. However, your call is important to us, so please leave your name, phone number or email address, and a brief message and we’ll get back to you as soon as possible. Thank you for your interest in Lydecker and Lydecker Law Offices. Professional tone Provide the caller with specific information Request the caller to leave specific information Extend gratitude for their call Professional Voicemail Greetings
Generally, people that call and leave messages are more likely to be ideal customers of your business. Your voicemail message is often not much more than a formality to the person calling.