I've said it many times before, and I'll say it again: I am Lajos Egri's bitch.
The Art of Dramatic Writing is in widespread use as a textbook for college screenwriting classes, and I believe it applies equally to theatre and fiction. It is widely considered definitive and I highly recommend you read it if you haven't.
Here's the cliff notes:
1. Premise is the basis of everything. Premise is not a vague sense of "general theme" - it is the one sentence underlying message the whole book is trying to prove. Famous example: Romeo and Juiliet's premise is "True love defies even death." The premise is the roadmap, the direction I'm going. If my goal is to run a race as fast as possible, every step must be taken in the direction of the finish line, no meandering. If every word I say does not serve to prove my premise, I'm saying extraneous shit.
If a book is written correctly, the premise should make itself obvious. If it doesn't, that's a problem.
2. Character defines plot. All actions must be based in necessity - they must be the ONLY possible thing that character could have done in that situation, given who they are. Never, never make a character do something because you've scheduled it to happen. A coward will not jump in front of a train to rescue a damsel because it is time to be a hero - a real coward will stand there and watch her die. If one wants to write a story about someone being heroic, one better create a hero first. If you don't absolutely believe that OF COURSE it had to go down that way because HOW ELSE could it have gone, I've fucked up.
3. Point of attack is knowing when the curtain should rise and when it should fall - not having any extraneous shit. Everyone has at least one climactic moment in their lives, but most of the reality-tv footage of the minutae needs to end up on the cutting room floor to have a concise two hour drama. The story begins right in the imbroglio and all scenes must exist to show the character-driven actions that prove the premise. If I'm not following both rules 1 and 2 for even a moment, it needs to go.
That is my writer's mantra: Premise. Character. Point of attack.
In addition to Egri, I like these two Scribophile academy articles on the subject of passive vs active voice and show vs. tell.
Thank you for taking the time to read this, and to exchange feedback with other writers. If you'd like to exchange with me, head over to scribophile.com and join the Ubergroup.