I transitioned to no-poo by just gradually using less and less shampoo less and less often. I just scrub and rinse with my hands and water and then add a bit if herbal conditioner on the ends f my hair, because it's curly and they get super-tangled.
In soft water, I didn't use anything else. In hard water I still don't bother with acv or anything else (I have read of people finding these harsh over time), but I do keep a bottle of high-quality herbal shampoo around, and I use it maybe once a month or when I feel like there has been some build-up that's bugging me. I just find that hair doesn't really need much of anything once you give your oil glands, etc a chance to adjust to not being stripped all the time. Same with my skin, actually. I just use water and use soap on my hands and hairy bits. The rest of my skin I just scrub with my hands and water and let it adjust the oils as necessary. Works great! :)