Odds of Getting In
You can always start a blog and review films on it. But will anybody read it? They will if you've got the right stuff.
If you have a great writing style and voice, you are extremely clever (like us), sharp, articulate, and can create or join a top-notch website, and you can manage to convince the studios that you're the real deal enough to get one of those fancy press passes to screenings, you just might stand a chance.
You'll put in all that hard work...and you'll still be just a small blurb on page two of Rotten Tomatoes. Well hey, at least people are reading that blurb.