Hi. This is Hayley at Clever Cakes. Thanks for calling. I'm sorry that I’m not able to take your call at the moment. However, if you would like to leave me a message including your name and phone number, I’ll get back to you as soon as I can. Looking forward to talking to you soon.
If the you haven't changed your personal greeting, a default system greeting will be played for callers. For example, "Please leave a message for John Smith. After the tone, please record your message. When you finish recording hang-up or press the pound key for more options."

There are many little things I instinctively look for and notice and one of them is a person’s voicemail greeting. I often conduct initial phone interviews and when someone’s personal voicemail greeting turns me off, the interview process is over. It’s their first and last impression.
It might be a short voicemail message that you’re recording, but you do want to make sure you hit all the bullet points. It also helps to speak eloquently over the phone and that works better when you are prepared with what you’re about to say. You are trying to sell yourself in this message so put your best foot forward. If you practice and write down what you’re going to say, you can get rid of all the awkward pauses, ums, and stumbling over words.