My 2018 NaNoWriMo novel was a murder mystery set on a starliner. In
April 2019 I was contemplating revising it, so I wrote a summary
of some Internet research about writing mysteries, mostly
from Writing Excuses.
I wound up going a different
direction, but now I am
coming back to that novel. So I’ve read a wider variety of internet
sources, listed at the end of this post, and have synthesized what I
learned into a summary of my own. I strongly advise that you read the
original sources, too.