File this under “super obvious yet I always seem to forget it.”
I don’t write romance (I totally respect people who do, though!) but this is also great writing advice in general! What is preventing the protagonist from achieving their goal?
Why can’t these two people be together now?
Why can’t the mystery be solved now?
Why can’t they overthrow the evil overlord now?
If you don’t have a solid answer for these questions, that’s a good indicator that the plot could use some more work.
Also test your answer a little bit. If it’s as thin as they’re just refusing to sit down and have a simple conversation, you might want to re-think how things are going.
As a beta reader/editor, I tend to ask this question a lot: “Why are they doing it this way when there’s a much easier path available?” That’s not to say that they should take the easier path, because that would usually be boring. Instead, the point is that the question needs an answer–either eliminate the easier path or give them a very clear reason for not taking it. (And if I’m asking the question, that reason isn’t as clear as you think it might be.)
I find it very difficult to root for characters who have a sensible option available and just don’t take it. If the only reason is “Because there wouldn’t be a story otherwise,” you haven’t actually found the story yet.
