@ OP, it depends on the platform you're running.
What are your components?
Before you start, you should know some of the basic rules though...
Intel platform:
- FSB x CPU multiplier = CPU frequency (Ex: 333MHz x 9 = 3000MHz = 3.0GHz)
- FSB x divider x 2 (DDR = Double Data Rate) = RAM frequency. (Ex: 333MHz x 2/1 x 2 = DDR 1333)
AMD platform:
- HT clock x CPU multiplier = CPU frequency.
- AMD platforms also use a divider but there is also the NB clock to take into account.
- You can only damage your components by increasing the voltages to ridiculous levels. Modern CPUs will shut down if the temperatures are too high. (This rule applies to both AMD and Intel platforms)
- Voltages left on auto will be increasing automatically, often too much, by the motherboard. This is why you should try and set all voltage manually if you can.
- You will need a temp monitoring program and a stress test as OS tools.
CoreTemp Prime95.
- Your multiplier will always be set at the max (assuming your multi is locked), so you will need to increase the FSB/HT clock to overclock. Increase in small jumps and test for stablity in between. Run the stress test for 5-10 min in between every jump and then for how ever long you want once you think you have reached your max overclock.
- Instability can usually be cured with an increase in Vcore, or NB voltage once things get a little bit more complicated, so once your stress test program brings up an error, re-enter the BIOS and increase the voltage very slightly and test again.