One of the hardest things to get right is the balance of discussions.
How many should you post? What type of discussions should you post? Which should you highlight? Look at this screenshot from UK Handmade.
Here you see a mixture of discussions designed for status-jockeying, bonding, and a few that convey information.
Notice a few things. The conveying information discussions are the least popular, The discussions that ask a question in the subject line are typically the most popular (or express something to do in the subject line).
However, this is a mature-stage community.
In the inception stage, we would suggest having a mixture of 30 / 70% open/closed discussions, without about the same levels on bonding/status jockeying discussions and those that convey information (i.e. have more than convey information – people don't know each other well yet).
As your community matures, gradually shift this to more open discussions which encourage members to reveal more information about themselves.