Most important of all: What cooling solution do you have in the CPU? What are your ambient temps and CPU temps at stock clock?
Your goal should be easy to achive and will give you a small FPS gain. Maybe 2-4FPS Average.
I don't have the FX myself. I have the old PhenomIIX6 1100T clocked to 4Ghz. Been running it for years like that and it is still going strong.
As for the overclocking itself, try to google for articles covering overclocking. Keywords that could be useful for searching: Piledriver, bulldozer, overclock, guide