Overclocking a Sapphy HD7870

Well, I've recently aquired the Sapphire Radeon HD7870 Ghz (the one with the cyan line that kinda looks like an MSI), and, being the noob at overclocking that I am, I need some advice.

I know the basic drill. Pop out yer MSI afterburner or CCC and OC away, but I need to know the risks, what not to do and that sort of stuff.

Can the syndicate give me some advice?

You could use this: https://www.sapphireselectclub.com/ssc/TriXX/

Looks nice, thanks man :)