I believe honesty and creativity is the key. Understand that in order to increase your callbacks, you need to pique the prospect’s interest without raising doubts or fear.
Wondering why this is? We can thank the serial position effect. This psychological phenomenon says when you show people a list, they'll remember the first and last items the best. That means when you're trying to grab a prospect's attention, you want to be one of the first or last things they hear.

Sample Voicemail Message #1: Note: The best voicemail message you can leave is one with a specific purpose that addresses the needs of your prospect or client, and offers them a solution that is worth them taking the time to call you back to learn more about. Here is the classic template – adjust and adapt it to fit your product or service.
5.) If you’re calling a home line, and know the family, it’s nice to say a group “Hello” before leaving a message specifically for the person you called. Say something like this: “Hi everyone, it’s Maralee. Hope you’re enjoying Spring Break! Janet, I wanted to see if you and I could meet for lunch one day next week. My schedule is pretty open, and we could pick a restaurant near your office. I know your lunch schedules are tight. I’ll give you a call back at 7:00 tonight. Or I’m around all afternoon, so give me a call!” (Boy, home lines are becoming rare, aren’t they? We gave ours up a couple of months ago.)