From my 20-year experience as the co-founder of companies in Viet Nam and Malaysia, it is a very crowded marketplace, with very little, if any, differentiation between products. So my starting point was to produce an all-natural shampoo made by saponifying all-natural plant oils. A natural starting point was to saponify coconut oil that was in plentiful supply.
Our shampoo was an instant hit with consumers who did not want synthetic shampoos. I ended up Private Labelling for many brands globally. My shampoo was a massive success.
So my advice is to first think about differentiation in this very crowded marketplace.