overclocking is the procedure to get better performance from your computer by making the speed of the ram/cpu/gpu faster.
overclocking is done mostly via BIOS for proccy and RAM, and via OS for GPU.
yes, anyone can overclock their components. i have overclocked my hd6770 to 950 Mhz/1340 Mhz (thats ~23% overclock)
the first thing you should check is temperature. if your current cpu temperature is 60-70 C, then after overclocking, it will go to 80-90 C easily.
hence, you need good cooling solution.
one of the cheapest and best performing cpu coolers are these 2 : Corsair A70 and the CoolerMaster Hyper 212 Evo. both are around 2k-2.5k. excellent performance for such a low price. get either of them, if you want to overclock.
2nd thing is power supply (psu/smps). make sure you have one of good quality. bad quality ones will die very fast and kill your whole pc.
Theitdepot - Top 9 Products
^^ some good psu's
3rd thing is, motherboard. does your mobo support OC? does it even have the options of OC?
eg : intel motherboards usually DONOT have OC'ing options.
make sure you have a good/great/amazing motherboard before attempting this, else it will blow up.
dont even attempt OC'ing before you have read and re-read all the proper articles.
just google for those articles.
give us your configuration