If you don't know what hardware you are working with specifically, and you don't know what to do you're going to end up breaking something, or worse. So be sure and read up as much as you can.
I could type a two page post about Overclocking, building a water cooling systemto do it, or going with a peltier or phase change etc. But tbh until you get the basics down and experiment with some old junk if you have it laying around, it'll probably confuse the hell out of you..
I don't think its worth it too much these days with some of the more modern CPU. As technology advances raw clockspeed will continue to become less and less important. RAW Mhz (or Ghz if you will) is like Horsepower, your CPU's architecture is the drive train efficiently turning that power into torque to get it going fast off the line. You can have all the horsepower in the world, but if you can't properly apply the torque it generates, its useless.
Back in the old days if you had a Pentium II/III or AMD K6 or whatever, even a 486DX, if you got 50mhz it was the bomb and it was noticeable.. Today it would take a couple hundred Mhz and you still would have a hard time spotting the difference outside of benchmarks.
I OC'ed my Core 2 Duo for a while, with the stock cooler and crappy TIM, no special paste or anything. Didn't notice much for my couple hundred Mhz and it ran a little too hot for my liking. So I just sit happily at 2.1Ghz.. If I wasn't poor though I'd probably be at 3Ghz or more with some good Water Cooling.
Just make sure you know what you're getting into. It can turn into and obsession/addiction, and its not worth it at that point for another 10pts on 3DMark or 1FPS in Call of Duty, etc.
By the way you still need to do something about your signature. If you put both images on the same line, it will meet the Forum Rules requirements. Or you could just dump the bottom one. There's no sense having the same image for your avatar and sig.