Uh, my very first film was kind of a fluke. I found an actual legit job on craigslist (which has never happened since and I haven't heard of anyone else who has either, haha). But it didn't really go anywhere,
tbh. My first ~real~ film, as I call it (after I graduated and my first actual attempt to make this a career), I got from this guy-- okay, let me start by saying this is an industry of nepotism.
While location scouting a project I quit after like a week because it was shady as hell, I ran into a dude shooting a small film. He turned out to be a prof at my school, so I took a film bootcamp with him.
Then he referred me to this guy for a short film. Then the 1st AD from that short brought me onto my first real film. And p much every job since then has been a referral.