Okay, anyone who has gone through Language Arts 101 or written their fair share of stories, both long and short, knows what a plot is. First of all, you need a main character. This person has a problem to solve, you see. (That's where the objective or goal comes in.) Then, of course, he/she meets with some resistance that makes it hard to get to that goal. (Enter: the antagonist -- person, place, or thing.) So, they do battle of some sort. (Yep, you got it. That's the conflict.) Finally, in the end the problem is solved, or not. (We call that one resolution.) Simple, right?
Well, maybe. The problem is when we write we might forget to resolve some of the issues, especially when it's a novel-length work. It's all those loose ends we talk about. Or we might write ourselves into a corner and can't figure out how to get out of there. I always hate that one because then I have to go back and revise what's happened before, i.e., backtrack the character's steps to a point where things were fine with the story. It's kind of like the recovery/restore feature on your computer. You know, the one where it asks you if you would like to restore by going back to the point when your computer wasn't so screwed up? That kind of situation. And then again, the problem might be because you've forgotten some tiny details about what your character has done, and as a result the resolution is confusing or it just plain doesn't work! (Here is where I say TAKE NOTES. Always keep a notebook and jot down details of what you've written that day, hour, or whatever chunk of time it is. Don't trust yourself to remember it later. WRITE IT DOWN!) I like to write a short summary of each chapter. And if I have a summary of events, which I often make out ahead of a writing project, I will go back and jot down any changes I've made as I get into the writing. (And there will always be changes. Trust me.)
All the above is called the LOCK system, according to James Bell, author of Plot and Structure. L is for Lead character. O is for objective. C is for Confrontation. And K is for Knockout. This is a novel (no pun intended) approach to naming the elements of a plot. Bell suggests that you always keep the LOCK system in mind as you progress through your story. You might keep a chart of sorts to describe and detail what your character has experienced and accomplished. After all, there may be mini-LOCKs within a novel or more than one character who is accomplishing things. Of course, as Bell mentions, solid plots have one main objective that the main character deals with throughout the story. This should be made obvious to the reader. In other words, what is the character trying to accomplish here? If the reader is aware of that, and of course, how the character does accomplish it, and if it's done well, then you've done your job.
So, bottom line: Use LOCK, take notes, and of course, revise, revise, revise! Until it's perfect :-)