OC help

[silent-circuit]

Got my 2500K to 4.5Ghz easy on this Z77, just used the default Intel "lazy mode" OC options and turned voltage offset down slowly over the course of several boot cycles, but ideally I want to get this thing closer to 5Ghz. Any tips and tricks for someone who's been ignoring this side of things for a while? It's on air, a Prolimatech Megahalems with a pair of Panaflo 120x38mm fans in push-pull.