I always end voicemails with my phone number. The reasoning? First, it's his cue to wrap up. It keeps him from rambling and gives the prospect a clear call to action: Call him back.
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."

“Good afternoon. You have reached the office of [your name]. I will be out of the office beginning on [date] and will be returning on [date]. Please leave a brief message with your contact information, and I’ll be sure to get back to you as soon as I return on [date]. If this is an emergency or you need to speak with someone before I return, please contact [name of colleague/supervisor], [their job title], at [their phone number].”
A compelling sales voicemail won't be particularly effective if your prospect has no idea how they should respond. You can't just rattle off what they stand to gain from leveraging your product or service and then hang up. Always offer some next steps or insight on what they should expect next — like another phone call or a follow-up email.