Using concise and simple words in your scripting helps ensure callers can comprehend what is being said. Although a complete on-hold message can be quite lengthy, it should include concise and to the point single messages. Aim to get each message across in around 35 to 40 words. Remember, what may read great in written word doesn't necessary sound great said out aloud.
The most engaging messages are slightly unique in nature. They combine a mix of clever scripting and music. Slight humour is often used to promote a product or service and is usually quite effective. It's also very important to choose both the written and spoken tone that appeals to the characteristics of your audience. If your target market is the younger generation, a script that includes slang words and is quite laid back would be an excellent choice. If your target market is primarily business professionals, then a more articulate choice of words would be more suitable.

As a bonus, here is an example of our own holiday voicemail greeting here at OpenPhone:
Calling a Number To Record Select By Calling a Number to Record. Give the file a name. Optional: Leave a note for yourself to tell what the file is for. Type in the Phone Number or Extension you would like it to dial. The user logged into Configuration Manager must have services assigned to them for this to work. Select Call Now. The system will call you. Follow the prompts to record your greeting. Select Finished Recording. Click Save. Click Select on the audio file you would like to use.