5. Be Brief. The best after hours greetings are brief, direct, and punctual. Do not waste the customer's time and give them a reason to hang up by adding in unnecessary details.
Sending an email to each prospect before you call gives them an additional way to get in touch with you when they're ready. As you're leaving your voicemail, mention that you've sent them a quick email as well that has further details on who you are and the purpose of your call. As Florin Tatulea of Loopio explains:

For many small businesses, the announcement will send the caller straight to a voicemail box. But larger organizations may decide to direct callers to a phone menu or forward the call to an external destination, depending on the situation. These options can include: Listing individual voicemail boxes for different departments or employees. Forwarding calls to a professional answering service. Giving callers an option to connect to an after hours or emergency support line. Directing calls to a personal cell phone. Presenting menu options for additional recordings about office locations, ongoing promotions, and other information.
The importance of voicemail in the customer care sector has not diminished despite the arrival of newer web technologies. VoIP applications let the businesses use voicemail service with flexibility, as it is. The users need not rely on extension terminals when they use VoIP services. A strong internet connection is a prerequisite and the pre-configured phones can be used – both for calling /receiving calls and for automated custom greetings. IVR feature redirect callers to the right virtual extension where their needs can be addressed. This can be done anywhere through a web portal access and an internet connection.