It’s important for fiction writers, regardless of genre, to do at least a minimal amount of research about the subject of their book.
In my case, I usually write about a lawyer with her own office. That’s a subject I know about from experience.

Me, in my law office, ages and ages ago! 🙂
However, lawyers don’t memorize every law on the books. What lawyers do is compare client situations to those that are in case books (or cases found online, these days). It is, therefore, in a lawyer’s nature to do a lot of research, anyway.
In the case of my new protagonist, Erica Jensen, retired Marine, opioid addict, post-traumatic stress survivor, and unlicensed private eye, I have no direct experience as a veteran, let alone a Marine.
Of course, I have a tendency to compare law school with the military. In my experience, law school was a bit like boot camp for the mind.
Nonetheless, being a lawyer is a very different experience from being a Marine. This is why I’ve made the effort to read as much as I can about the experiences of female veterans.
This video review is for one such book.
I have learned so much about female Marines and other veterans, not only from reading books, but from talking with actual people. When it comes to research, nothing quite takes the place of primary research.
And, in case you didn’t know, click here for the difference between primary and secondary research.
PS: To “shoot like a girl” is actually a compiiment! I forgot to mention that in the video review. 🙂