Many busy businesses utilize auto attendant greetings to make a great first impression, however, if your business relies on the personal touch of a live receptionist, it is important to have a plan in place when that position is unstaffed. Make sure your voicemail greeting contains the useful information that your receptionist would normally provide. This could include: location & directions, office hours, website URL, or social media info, as well as any pertinent company information.
Don’t rush. It’s important to speak slowly and clearly when leaving your next voicemail greeting. Have you ever called someone and the message sounds like one big word? Don’t be that guy. Pronounce your words and take pauses between your sentences

Some phone systems allow employees to specify a primary greeting and set secondary messages to cover absences or vacations. When creating an individual voicemail greeting, clearly identify yourself, your role, and your company, and let the caller know when you will be able to return their call.
When your small business is closed, ensure that your callers know that! If appropriate, you might want to reiterate your business hours to manage callback expectations.