do it via bios, and save your overclock settings - so you can revert if one fails.
enable XMP first. make sure it's stable. check your base temps and load temps.
then start with a .3 Ghz multiplier update usually no-brainer, monitor your temps and run that for a while for stability and you'll have a certain comfort zone.
Then adjust the next increment when you feel comfortable noting that you'll need 1.35V for the RAM and may have to increase the core voltage slightly as you OC.
The problem with software OC's is you rely on too many values you don't directly control.
I have never really overclocked before and did for the first time with my new processor the 9700k. Is it safe to do so with the Intel Performance Maximizer software? Also, Can I set the XMP profile up for my ram at the same time?