This paper discusses about the approach towards effective power oscillation damping, root causes for the genesis of power oscillation and various methodologies adopted from the very beginning to mitigate oscillations. Complexity involved with AVR and PSS in damping oscillation are investigated and to overcome this necessity of PSS tuning is simulated and verified over Eastern Region system and generator. The power oscillations, if not controlled within time, may aggravate the entire power system functioning which may lead to collapse of the entire system. Tuning of PSS is a matter of great concern as the ill tuned PSS may itself lead system towards instability which is also discussed and a guideline for tuning PSS is also suggested as deployment of tuned PSS enhances the overall system stability of the grid by shifting the eigenvalues of the states of power system towards left half. Impact of PSS over eigenvalues is also discussed. PSS/E All India dynamic base case is used for simulation of eastern region and for various case studies.