Users often don’t invest enough time into their messages, resulting in incomplete, unprofessional, or otherwise under-whelming greetings. Sure, crafting a greeting doesn’t sound all that complicated; however, there are a number of pitfalls users can fall into—i.e. informality, terseness, sincerity, lack of direction, and more. While none of these sound too catastrophic, they are often interrelated. As such, they tend to worsen any problem. For example, humor can cause informality, worsen ambiguity, and weaken sincerity. That being said, users should strive to avoid ALL these pitfalls.
Recording company voicemail can be really simple, like speaking your new business voicemail script into an iPhone, or you can set up voicemails across your entire company at a highly professional level.

Many businesses try to save money by selecting an amateur voice actor from inside the company to provide a recording. The trouble with this is that: The “actor” is typically an amateur with no voiceover experience. The company doesn’t have personnel with directing voiceover. The “actor’s” goal is to finish quickly and get back to work, not make the best-quality recording.
Expand your opening to with 'Thank you for calling [insert company/individual name]' or 'You've reached the voicemail of [insert company/individual name]'. This personal touch goes a long way towards building a rapport even when you're not available to answer the call directly.