What KIND of DISCUSSION ?

Well, I would suggest starting with an interesting and well thought out discussion topic. Then, I would suggest responding back to all the people that reply to your discussion. This will not only make the discussion more interesting by having back and forth interaction but also it will draw more attention to the discussion by having active participation. You should also try responding to discussions that other people start, because people that see you around posting and responding on discussions seem to be more apt to check out your discussions, because they will recognize you, especially if you generally have something interesting or informative to add to the conversation.

Respond on those started by others