Overclocking has to be set up in the kernel first. Currently our kernel maxes out at whatever cpu it came with. In order to go higher, the kernel must be modified to allow higher frequencies. Until this happens, it will be impossible to overclock. I heard that underclocking works though.
As for preformance in general, the only thing you can do is keep your ram from getting used up. There are all kinds of don'ts but very few do's.