I don't want to share more on the specific field.
I did not start with a plan. As I say in the post, I started with writing one or two forum posts on the topic. People thought these were valuable. I read a few books on the topic. I connected with a few people as a result of this, either asking for advice or giving advice. I gave feedback on the writing of others.
I focused on the same field during part of my internship, which also helped.
You did not miss anything.
There are not many opportunities in the field I was exploring. I also had a very high bar, given the job I was already in. Otherwise, I would probably have applied for more positions.
Edited for clarity.