Without the fake tone of excitement in your voice, the listener understands that the specific question you're posing is just as meaningful to you as it is to them. And the more the listener feels the message is meant for them and only them, the more likely it is they'll respond.
Thanks for all the great advice you share on the Manners Mentor blog! Here is my situation. I hope you can help. Sometimes I’m good at leaving a voicemail that’s to the point, but most of the time I feel like I’m a babbling idiot. I never know how much information to leave. How much is too much? How much isn’t enough, especially in a professional setting? I would love to know your thoughts on this. Best wishes for a wonderful week!

Although it is okay to give a little bit of information, keep in mind the goal of your voicemail is to take the next steps in the conversation, and not to have the whole conversation then and there in your recording.
If I’m not available, just leave me a voice mail. Again, either way, it will be good to know what’s going on. Thanks in advance for that, and I’ll look for your call. You can reach me at (your number). That number again is area code (your number). Thanks ________.”