1. Finding indie filmmakers and giving them enormous tentpole blockbusters
"Hey! You directed a single modestly successful indie film - therefore, you'd be PERFECT for this 150 million dollar summer tentpole blockbuster franchise film!"
THAT'S the current thinking in Hollywood today, for whatever reason. Maybe it's because they figure these indie directors will be in so over their head that they'll be easy for executives to control? Maybe it's because most blockbuster shots are so effects-heavy that it'll mostly be the VFX team doing the important directing and these indie directors will just try to make the dialogue/acting pop during the 15 minutes of screentime that don't involve dinosaurs or explosions?
Either way, they'll definitely be able to channel the magic of their four-character one-location dark comedy into the 55-minute rotating battle scene.
Also should be noted that Colin Trevorrow's next film as a director is Star Wars Episode IX.
2. Releasing MAJOR MAJOR spoilers in the trailers
"You know what people hate? Genuine surprise and excitement! Let's make sure every possibly interesting plotpoint is in the marketing materials so that everyone knows about them before walking into the theater!"
Seriously - people like some air of mystery to exist before buying a ticket. After all - if you know all the important stuff, what's the point of actually SEEING the movie? Surprising stuff happening in movies is fun, and leads to positive word-of-mouth. One of the entire reasons The Sixth Sense was so successful was that people told their friends that they would NEVER see the ending coming, and people went to the theaters anticipating a surprise. You know what would have made no one wanna see The Sixth Sense? Revealing that John fucking Connor was a secret Terminator in the damn trailer. I mean, that would have ruined The Sixth Sense for a lot of other reasons too, but you know what I'm saying.
The trailer for Terminator: Genisys (ugh) and posters revealed that series mainstay John Connor was secretly a Terminator in this timeline - something not revealed until late into the film:
The INITIAL trailer for Southpaw revealed that Rachel McAdams' character - one of the above-the-title actors in the film - was killed early in the film:
The trailer The Martian - a film that won't come out for a few weeks - reveals that Matt Damon is able to contact NASA, and that his crew defies NASA's orders to go back to Mars to retrieve him. In the novel, both of these are pretty major twists that don't happen until deep into the story:
3. Releasing trailers before the effects shots are done
For whatever reason, movie studios feel the urge to get trailers out for their films a good six months before the film actually premieres anywhere. I'm not sure WHY they feel the need to do this - really, it's only in the month leading up to the release where it's actually important to remind people that your movie exists and what the date is. It's not like anyone is planning their movie-seeing schedule six months in advance. Beyond this, there's another issue: when you're promoting a movie six months in advance, there's a good chance the movie isn't anywhere close to done yet, and will look pretty shitty, with incomplete or entirely-missing effects shots thrown in just because.
Here's a shot from the first trailer for Jurassic World, featuring hundreds of guests fleeing from...nothing?
Here's the shot from later trailers, with the effects ACTUALLY ADDED SO THAT PEOPLE ARE RUNNING FROM SOMETHING:
And in the recent Fant4stic, the other-dimensional Planet Zero changed from a lava planet to a...greener, glowier lava planet?
4. Including stuff in trailers that aren't in the finished film
Speaking of releasing trailers too soon - there's a lot of times when a movie will be sold on scenes that end up on the cutting room floor, so the cool thing in the trailer you couldn't wait to see in the actual film? NOT EVEN THERE. What the hell, movies?
It's almost impossible to list all of the stuff that appeared in the Fant4stic trailer that was just not in the finished film whatsoever - from Dr. Storm's narration about science and exploration and why Reed Richards is the key to everything, to Ben Grimm's baseball-playin' ways, to Johnny Storm's request for a heat resistant workshop (with a big-ass sunroof) - but the most egregious example is the Thing storming a military base...which sorta happens, on a tiny screen, viewed over a dude's shoulder.
All of the great Ultron dialogue from the initial Age of Ultron trailer basically never appears in the film, nor does the mysterious woman in the cave that the internet was endlessly speculating about for months:
"I'm gonna show you something beautiful...everyone screaming for mercy. You want to protect the world, but you don't want it to change. You're all puppets...tangled in strings..."
5. Coming out with like 9 trailers and releasing a constant stream of clips from the movie
Listen - I'm sure you THINK you need to release, like, 9 separate trailers for The Avengers, Star Wars, and Batman v. Superman, but the truth is you don't. People are going to see these epic huge blockbusters with an enormous built-in fanbase regardless. It's not like there's anyone on the fence after two trailers for Star Wars: The Force Awakens who's waiting for a THIRD trailer to really sell them on it. Not to say they shouldn't be marketing their movies pretty heavily so that they maximize awareness and attendance - just know that the entire internet is gonna show up the first weekend regardless of whether you make four trailers or one, so save yourselves some time and just do one or two trailers (and save us from being spoiled on basically the ENTIRE HULK VS. HULKBUSTER FIGHT).
Star Wars, Avengers, Batman - we're gonna see your damn movies, you can cool it with all the trailers that give away too much and don't even have stuff that'll be included in the film.