Agreed, that Group discussion can be tricky at times but most of times you will be given GD topic on current affairs or based on social issues so that you get ample chance to speak out and express your ideas.
With GD, selection panel tests you on communication skills, Expression of thoughts, body language, domain knowledge and top of all how you maneuver your talks to address your thoughts.
You need to speak at your turn with some new idea or come up with suggestions to extend and elaborate initiatives on the theme of topic.
Depends how do you speak and take up response from co group member in GD , that will ensure whether you are heading forward to be a leader in group or not.
Candidates who can express and have perfect Tete -a -Tete are likely to be at ease in GD.