What Are The Tactics Involved In Clearing Group Discussion(GD)?

A group discussion is generally held before the final or preinterview.
It has some definite purposes. most common of these are:
a) Judging the ability of the candidate to put across a point,effectively and assertively; without looking down upon or degrading the other candidates' point of view.
b) Judging the comprehension and information of the candidate.
c) Judging whether the candidate speaks as and when required, and to the extent required,without being too loud.

Naturally therefore, it would be BEST to prepare for GD, in the following manner:
1) Keep up to date with all current topics.
2) Listen carefully when everybody's making their point of view. Note down the important points.
3) When your turn comes, put your point in an assertive manner without being aggressive.
4) Do not interrupt when somebody else is making a point; rather, note it down and say about it when your turn comes again. Or you may take permission from the chair, after that person has finished.