Above all you must encourage the caller to remain on the line. Provide reassurance to your clients that an agent will be available soon and don’t forget to convey the idea that their time is valued and their call is important.
Regrettably for my purpose, the software requires that you add a "message on hold", which makes perfect sense for this devices intended purpose, if not for my own use. But I worked around the problem by recording a second of silence and then adjusted the software the effectively play only my cheesy elevator music.

So what can we do to avoid inflicting further musical misery on our own customers while they’re patiently sitting on hold? We could just go back to playing a ringing sound, or an intermittent beep just to let people know they’re still connected, but that would be awfully dull. The best compromise is relatively simple electronic music that doesn't have too much going on as the ideal choice for hold music as it requires far less refined sound quality to get a decent rendition down a telephone connection.
For example, if you have the same people calling multiple times a week and being put on hold for long periods of time, it might be useful to update your messaging more frequently so they are getting value out of the time they are spending on hold. The more specific and targeted your voice messages are, the more impactful and successful they’ll be as a marketing tool.