Instead of writing to inform people or to entertain them, you need to write your script as a way to create a conversation. You need to imagine what someone would say to another person and then put it on the page. Don’t be afraid if it feels like you’re talking to yourself — that just means you’re writing well.
You can create a professional sounding on-hold message with a few tools that you may already have on-hand. All you need is an audio recorder (this could even be your cell phone), a good microphone, and someone who’s willing to be your voice actor.

In 1962, inventor and entrepreneur Alfred Levy found a loose wire touching a metal girder at his factory. It amplified the broadcast signal from the radio station next door and transmitted the audio through the loose wire to calls on hold. Four years later he patented his work, and music on hold was born.
In his role building Cisco’s first version of IP phones, he was aware of Cisco’s need for a piece of music to use as the default hold music for the new system. Cut to several years later, and their high school composition has become the hold music for the world’s most popular phone systems with over 65 million IP phones sold.