Overclocking is really a matter of personal preference, depending on how much power you are happy with your card drawing, at stock clocks (without adjustment) you will see the card pull max power. I suggest that you should clock as low as the card will go and step up until you are content with the power limit you want to use.

I have a similar card in a 1070ti and i run it at +120 core clock +400 mem clock and power limited to 120w


again, it's personal preference and where those are the settings that I use, another may prefer different on the same card.