I regularly use shikakaipowder for washing my hair. My hair is naturally dry and curly and the best washing method for me, is to have an oiltreatment the night before washing (or a few hours before washing). Just use some olive or neem oil (those are my favourites for pre-washing treatments) on damp hair and wrap your head in plastic foil.
Use just a little bit of shikakaipowder (2/3 tablespoons will suffice) mixed with some water into a past and just dab it on to your hair, let it stay for about ten minutes, then give your hair a gentle massage and rinse it out ; after that use a (cone-free) conditioner.
When I'm rinsing the conditioner out of my hair, I already feel the softness that washing with shikakai always "provides". It is one of the moste gentle ways of washing my hair (ghassoul is also great!) and I have to do it this way so my hair benefits the most!