I will start with the physical side of things i made sure i had plenty of fans i even made a hole in the side of my case so it would blow on the back of my cpu. I have artic silver 5 to have maximum heat transfer with a heatsink that can cool up to 3.5GHZ that will keep it cool along with 5x 80mm, 2 PSU, 1 Graphics card and a 120mm fans.
Now i have a P4 2.8GHZ FSB 533, clock thingy @ 133 my ram is 512 DDR333 @ 333.
I went into the bios and turned on my warnings for cpu fan, so if it fails it will save my CPU i also turn a Temp warning on set at 60C. I overclocked in the bios as i didn't want to use any crappy programs like easytune. I haven't changed my voltages as this will shorten the life time quite alot RAM musn't exceed 2.7V and P4 CPUs shouldn't exceed 1.70V.
I uped my CPUs Clock speed from 133 to 160 odd in doing so it automaticaly ups my RAM from 333 to 400 odd but my CPU doesn't allow me to have RAM over 333 so i had to downclock it to 328. I ran Prime95 for about 7 hours no problems and has been stable ever since. and is at 3.44GHZ
If you have money which i don't you might what to buy a faster CPU and a vapochill and reach 4Ghz if you dare!