am I correct in assuming that you are asking how you find the way how you are setting yourself apart from other trainers?
My “niche” is training older adults and/or training people who have medical problems which go beyond the scope of most other trainers. It was something I was interested in from the very beginning of being a trainer, and my continued education was focused in that direction.
Having said that, I also recognized early on that my older age would also make me a better match for clients of this description. As appealing as it sounds to train athletes, I was quite sure that I am not the likely trainer who would be sought for athletic performance (unless they get injured, and I am back in the running).
So: for me it was a combination of ‘follow your heart’ with a dose of reality.