One approach is to anticipate what members are going to do.
You can look at what products you sell, what categories you cater to, what audiences you have, and set up different areas of the community accordingly.
You can anticipate what features they’re going to want and ensure you have them too.
Another approach is to respond to what members are doing.
You can look at what members are talking about in your community and create groups, categories, and features accordingly. This is where we get Twitter’s hashtag and thread features. It’s where we get Facebook memories and StackOverflow’s new thanks button.
Starting with a relatively blank canvas and quickly responding to demand is a lot better than trying to anticipate it.