There is no secret. It's all here, it's all in KD's books, it's in the BE set of articles, it's in Abdul Mohed's book, it's in the Curry Guy's book etc. etc.
Over the past 18 months I have befriended a chef who has his own takeaway near St Andrews. When we started talking cookery he realised I knew a bit more than the average customer and he has made me other curries not on the menu, but more akin to what he, his family and the other chef's eat. In return, I went to the Halal store, bought some chicken and made some curries for him. He was very complimentary.
Late summer, early autumn, I took up 6 curries to my friend and his wife who run a coffee shop just outside Aberdeen. They were gobsmacked and have asked me to put on a curry night at the coffee shop. A date has still to be arranged and I am anxious about cooking for 40-50 people but we will work on the logistics at some point and I will get assistance from their chef and from themselves.
So, from a domestic point of view, I think other people's reactions are one of the things that tells me I am there. My partner says I don't really appreciate how good my curries are, and I think she may have a point as I am probably my own toughest critic.
From a commercial point of view, I have no experience whatsoever so I'm not even on the starting blocks never mind being 'there'. I think others like 976bar (Bob) and Chewy would have much more to say on that subject.
But for the moment I think I have got my curries to a consistency that I am happy with and I take great pleasure in cooking for eating's sake.
As for naan bread, well that is a different story altogether....