7. Ensure That Your Characters Always Have A Goal
Ultimately, I think
Prometheus is disappointing because - despite all its grandeur - it doesn't really have much of a plot. Hear me out. I mean, it has a loose story that emerges from an extremely intriguing premise, but our characters eventually find themselves trapped in a screenplay that spends much of its time subjecting them to a series of brutal events with no real motive or pay-off. And that's because the story is so frustratingly ambiguous. Wispy at best. When you're writing anything of the blockbuster variety, though, the most important thing is to ensure that we know what our characters are shooting for at every point in the story. The moment that a goal is completed or goes out of the window (in this case, once they've completed their first goal, which is landing on the planet and exploring the ruins), you've only got a short space of time to set-up the next goal. Whenever you find yourself growing "bored" whilst watching absolutely any kind of movie, it's almost always because the characters aren't actively doing anything at that moment - the next goal hasn't been set up and we're in the process of working towards it. Notice that whenever anybody says "Let's do this" (or some variation of), though, that you instantly perk up.
Prometheus was crammed with ambiguous downtime. Ensure that your characters always have something to do, and that their agenda - whether actively pursued or not - is clear.