Pretty much just think of overclocking as putting a supercharger on your corvette. Sure it was pretty fast before, but you just gave it a boost to go faster.
You can find a ton of info from this website
http://www.overclock.net . It's where I learned, and still am.
Also a good page to compare video cards and how communities rank them.
http://www.overclock.net/t/502403/gr...-updated-daily
You can also use
www.cpuboss.com or
www.gpuboss.com . It help compares everything for you.
Overclocking is settings in the bios when you boot up. Motherboards now have the ability to overclock while you are already logged into windows. So overclocking depends on the cpu, motherboard and how you cool your system.
If you have any other questions feel free to send me a message. I will try and help you out.