Why this is a mistake: A story plot is a character trying to resolve
a problem. In most cases the antagonist is the one who introduces
For example, let’s say your antagonist wants to rob Fort Knox. Before
you write the book, you have to put yourself in the shoes of the antagonistand come up with the plan the antagonist would come up with. If you antagonist comes up with a stupid plan, the book is going to look stupid, and your protagonist is going to look less than heroic trying to stop the not-too-bright antagonist.
The solution: Take the time to really get inside the skin of your antagonist. Pretend you are the antagonist. Gather your cronies and minions together. Then develop your devilish plan for whatever it is you are going to do. Going to rob Fort Knox? Okay. First thing to think about: Why? What’s the motivation? Make sure it’s a believable one. Then develop a viable plan. A smart one. One you would have a really good chance of getting away with in the real world. One so good the FBI might come knocking on your door if one of the neighbors saw it laid out on your table.