Now then, that's out of the way, I shall divulge some of the countless things I have learnt through my experiences.
The first major point is your chipset. If you don't already know,
975 > RD600 > 965 ON A CLOCK FOR CLOCK ranking. (I don't like 680s
)That means, that @ 400fsb the 975 will be the fastest. This now know, one should also remember that 975 is still not necessarily the best. Usually the 965 can reach higher clocks.
266 - 400 fsb
so Fsb x cpu multiplyer (6300 is 7, 6400 is 8 and so on) gives you your cpu speed.
Cpu cooling.
Get something good. Ask around. Ask Wikid, ask me, ask people in the know. If you aren't sure, read up. But don't buy a cheap azz watercooling system and think you are gonna get a WR. Something like the Zalman 9500 or 7700cu are nice local and cheap products. Other than that, the Enzotech ultra-X and the Thermalright Ultra-120 are your best bets. Unless you want to go wc, but that needs its own thread
Next important thing is your memory. You don't NEED anything amazing. But it helps. My 667memory was pushed all the way up to 970 mhz. BUT everything relies on your ram holding up. Usually, dependant on the ram, cas 5 timings are used. Gives you enough space to get high speeds. For now we sacrifice timings for speed. When I first started reading up everybody was talking about the 1:1 ram multi. What this is, is your memory speed in accordance to your fsb. 1:1 is usually 266fsb to ddr 533. This is the most common setting for overclocking.
Since c2ds are such beasts, some chips like mine can get around 400fsb @ stock volts or lower. Lets use the 6300 which is a 7x multi.
400fsb = ddr800 = 2.8ghz.
If your pc can hit this without any tweaking, you are lucky
Usually we lower the multiplyer to make sure the memory can function at that speed and then raise the multiplyer thereby finding what is holding us back. If the pc doesn't post or is unstable before we raise the multiplyer, raise your vDimm. If its not stable after increasing the multiplyer, raise the vCore.Third major point
Chipset cooling. Tut tut tut... This is a pretty contraversial topic IMO. Some people say its totally necessary. I say, what every single overclocker needs, is a 120mm fan blowing against the board in the mem/chipset area, right above the graphics card. Lets you put more volts through your memory, and cools your chipset more than enough. Most boards won't want max volts through the chipset. Usually 0.1 or 0.25max even getting closer to 500fsb.
Stepstraps are bastards... UNLESS you have the dfi or Abit Quad gt. They are fixed on the 1066. Thats nice. On average, 400fsb @ the 1066 strap => 420fsb on the 1333 strap. Why am I always referring to 400? Thats usually the fsb where your motherboard decides its time to loosen up ITS timings, not the memory timings. So that kills performance BADLY, but allows you to OC that little bit more. So if you are trying a superpi run, stick to 400fsb and push it further in windows, if you just want a nice big OC, post at 450 or so. The only way around this, is to get one of these nice boards. The dfi is better btw
Last few pointers...
Put your pci-e clock onto 100 or 101. Keeps your hdds from corrupting. Lock the synchronous clock to 33.3mhz. Keep trfc pretty high too (Sub timing) I recommend over 40. Disable spread spectrum and C1e support too
As for voltages, 1.4 is safe-ish on air IMO and 1.45 on water for 24/7. I take no responsibility in this, unless its a good thing
Have fun and be careful.If anybody wants anything added, just give me a shout.
Dam... I didn't expect it to be that bad. I guess I could edit it a tad. But not right now. It was tiring 
