Janet highlighted something that isn't covered by the community management framework; training your members.
Who is responsible for training members to be better at what they do?
Not every community needs this, of course. But many, perhaps most, would benefit from an educator.
If members get better at the topic via participating in your community, they keep coming back to your community. Better yet, they feel a sense of joy, connection, and obligation to the community.
If you can facilitate the sharing of knowledge, facilitate crowd-accelerated innovation, and foster a genuine sense of desire to be better at what your community does, you can build a more active community.
Consider turning the best advice of your community into a free mini-course that members can take. Have problem-orientated live discussions once a week. Give people with the most experience their own columns/ask member areas for a couple of months.
The opportunity here is to take all the unstrucured advice in your community and structure it in a way for people to get better and then contribute fresh expertise.
