I just took a quick wander through my bookmarks, and I have to say that I break my own rules plenty in terms of what sorts of fics I will use to introduce myself to a fandom. I have read fics of every length, trope, and relationship-to-canon as my first-ever fic in a fandom I know nothing about. If I'm in the right mood and have the mental energy to put the work in, it's just fun!

So it's possible I'm actually the worst possible person to give advice to others on how to approach a new fandom fic-first, because I am That Person who honestly doesn't really mind how I approach it.....