It has been observed that often candidate are in hurry to open up group discussion. It happens so as they think that the one who succeeds in opening the discussion surely gets selected. It is a mere misconception. The fact is, you should think of opening the discussion when you have enough points to throw in
Great is the art of beginning but greater is the art of ending. Being a participant you should see that a GD does not end abruptly. One of the hallmarks of a good discussion is smooth ending and one must be able to envision the key points.