A helpful thing to remember when plotting out stories with a clear antagonist: he probably doesn’t know he’s the bad guy.
Alan Rickman’s character from Die Hard likely sees himself as George Clooney’s character from Ocean’s 11.
In Michael Clayton, Tilda Swinton is struggling to protect herself and her company. She sees it as a survival story, with herself cast as the heroic victim.
Even monsters, like the shark in Jaws or the velociraptors of Jurassic Park, can be heroes of their own story. In Aliens, the Queen is defending her brood. Once we understand that, the conflict is even stronger.
Whether you’re writing a thriller, a comedy or an action movie, always look at the story from the villain’s point of view. What is he trying to do? Besides the hero, what other obstacles are in the way?
Too often, we come up with the villain’s motivation (revenge, greed) and stop. Rather, look for what the journey is. We might only see a small part of it from the hero’s perspective, but knowing the whole arc gives us more to push against.
Have a little sympathy. Let your villain win a few times, but make him work for it.