Piece of string - what I use is about diameter of paracord, but a little bit "harder" - carried with string over left shoulder, bino's under right arm (I'm right handed). Play with the length and see what you like - I like mine just short enough they don't interfere with my jacket pocket on that side, but still enough play they don't bind. You can pull them up more under your arm to protect from mist/rain and they are always there.
You won't be the "cool kid" with the newest super techno bino harness, but you WILL be able to easily access/use your bino's, they wont interfere with your bowstring, and they'll be where you need them when you need them. Also they are very well protected there under your arm/along the side.
While on stand a lot of times I'll pull them around more to the front -say resting to the right of my belly button- and if a shot looks to be developing its a simple (now automatic) matter to slide them around to my side, or even around more to the back, like resting above the right kidney.
I use mine ALL the time - there are only 2 things I'd go back home to get if I forgot on the way to my tree - my bow and my field glasses. I've tried many ways to carry them over the last 30+ years, and this is the best way I've found.
R