So, you've got to make them feel part of the community they've created. As well as being welcoming, polite and reliable, it helps if you can tell a compelling story.
I know this is a somewhat vague term. And people tend to invoke it in different ways when taking about online marketing. But I think a good way to describe it is to liken a company to an ongoing TV drama. One major reason viewers get hooked is because they get to know the characters and their motivations, and end up caring about them as a result. It's this emotional attachment that keeps them coming back to watch the next episode. They want to see what they do to solve their problems and achieve their goals, as well as what happens to them at the hands of the other characters. They also enjoy the look and feel of the show along with the score.
In short, viewers are drawn to the human story and the way in which it is told. Now if you can inject some of those elements into your Facebook page, it will gather momentum. Needless to say you won't want to have any of the drama, violence, crime and general skullduggery that TV fans also find compelling! The story has to be overwhelmingly positive. But it's a story nonetheless.
So, how to do this? Well you could start with the characters (staff members), for example. Get each of them to share an update about what they specialize in and how they're trying to help their customers. Throwing in some personal background is also humanizing. Perhaps one of them is originally from a different country. So why did he come to Perth? What are his hobbies outside of work? Of course you don't want to make this stuff too personal and intimate. Could end up seeming a bit needy then!
As well as showing these actors, show them in action. Say you're a cafe, with a gun barista who makes spectacular looking lattes. Why not devote a whole sequence of posts, with photos, to her trademark approach to doing this. If it's a multistage process you could even draw it out over several weeks. One week, say, she could explain what kinds of coffee she likes to use most and why. The next she could devote to the coffee machine and its workings. The final installment could show how she turns the froth into little artworks ...
In every business there must be numerous compelling little stories like this that staff and management can tell online. As they keep doing this the momentum builds and a unique "meta-story" is created, drawing in more and more viewers, who eventually become fans.