Just follow the same approach as any other overclock... gradually tweak multiplier / frequency / vCore settings and stress test until you hit highest stable OC. Pretty well the universal approach.
Also, in your opening post where you say your OC attempt resulted in your system not being able to boot... means you tried to push your system too far. Again, change things gradually, one notch at a time, and if your mobo supports saving mobo configs, save each time you achieve a stable OC before pushing higher. That way, you can revert to a good stable setting without having to start the entire process over again.