Download MSI After burner utility. Install and run the app. You will see memory clock in mhz & core clock in mhz. Increment core clock by 5 and memory clock by 10. Check the system stability after each increment. When the system starts freezing, then that is the threshold point. Decrement both core and memory clock by a factor of 10 from that point to achieve stability.
Check the temperature levels as you overclock and keep it below 60c - 65 c in idle imo.
To know the results in games, download and install fraps to check the increase in fps as you overclock.
Post your results in this section.