1. Overclocking can be achieved in a few ways, the most common way is to increase the core multiplier to increase the clock speed. You can also overclock the base clock, but this is not advised for someone who is new to OCing.
2. It can be achieved with an unlocked CPU, and a motherboard with the available settings. I believe some non-unlocked CPUs can be slightly overclocked, but not much.
As far as overclocking your system, I would need to know which motherboard you are using. On a stock heatsink, it's not advised because it will most definitely decrease the longevity of your CPU.
If you are truly interested in overclocking your components, I would invest the money into some newer components that are more suited for the task. If you have a Microcenter near you, they have a very cheap combo on the FX-6300 and motherboards. It's a good platform for overclocking if you have a good cooler.