Well that is all depending on your hardware. So it still falls into that category of knowing what your doin. I think if you have the hardware support, you can cleanly overclock (like im doing right now) and have no worries if everything can support it.
But you always want to start at the small things first, the software, your registry, which you want to edit, and quite a few processes from Microsoft. That lagg free website I gave before is 10 pages of optimizing your software.