Well i guess u r asking abt gpu overclocking
There quite a few methods (procedures)
Here is a guide which i used and maybe useful for u http://www.evga.com/forums/tm.aspx?m=139251&mpage=1
Remember _ Patience is the key to overclock
N keep a tab on temps ( n power consmption too plays a imp role though im newbie at it )
Keep updating ur progress here
For OC'ing CPU and GPU, you must do it one at a time and step by step. I will take quite some time (especially stability testing) For CPU its usually done in the BIOS while GPU OC is done via program. CPU OC is done either by raising the BCLK or the CPU multiplier or both (voltage tweaks may be done).
GPU OC can be done with a variety of programs. moving the Core clock, shader clock, memory clock and voltage.
move these settings one at a time until you reach the limit then move to the next setting.