Find the highest overclock they hold stable at then wind down the power limit until the hashrate begins to drop off. My 1060 3GB cards' sweet spot nets 24MH/s @ 65% power limit. Also you should really check out other algos than ethash. ZCL (equihash) is seeing good results at the moment.
Thanks for the tuning tip. I haven't really messed with the power limit all that much, but I did just learn how surprisingly inefficient the "private label" PSU in my Cyberpower (a semi-custom brand at Newegg) is when I replaced it with a mere 80+ Bronze model from a local retailer (Best Buy) and power draw went from 400W before to about 240W now... that's just crazy!
Yeah, I know the Nvidia cards are much better at Equihash and Lyra2v2 and I've had the twin 1060s mining ZEN (on luckpool) for the last 5 days or so and am up to a whopping big 0.611 ZEN. The big jump in difficulty the last couple of days has me thinking I'll move over to something that isn't on fire at the moment (like that eternal disappointment, VTC).