3. INCREASE THE VOLTAGE
You may also need to increase the default voltages while overclocking. Sometimes, a voltage boost is what is needed to make an overclock stable, but you'll want to do this in tiny 0.05V increments. Playing around with voltages is always risky, and we wouldn't exceed an upper limit of 1.35V.
The Advanced Tuning panel lets you change things like the reference clock and voltages.
The CPU Stress Test will come in handy for assessing long-term stability. Overclocking is an art more than a science, and it is often a felicitous combination of trial and error and sheer luck that helps you squeeze the most out of your CPU.