I use 1/4 cup apple cider vinegar mixed with 1 cup of water (if I recall correctly, that's the recipe from the Curly Girl book). I use it once per week by spraying it into my hair until it's saturated. That takes about 1/4 of the mixture. I leave it in for a few minutes, then rinse, condition and style as usual.
Couple of inches past shoulder length 3A. Shampoo every 3rd or 4th day w/ baby shampoo; Tigi Fashionista conditioner; back to Condition 3-in-1 mousse . Alternate days water rinse, conditioner and mousse.