1. You defy the laws of physics and other natural laws, and sometimes break them. For example, how can you have a window in the ceiling with light shining through when it's an underground room? If it's not completely underground, you need to explain this. I have 'warped' people from a muscle car to a minivan in the space of a page, and without the benefit of a transporter. You must make sure that people and things are in the proper place. Don't forget the correct time, too. I am notorious (ask Nat) about skipping over days. In Sirenz, we had to map out the days just so I know where the action is (apparently I like to breeze over to the weekend...) Do a timeline, it helps.
2. I, I, I... As Mr. Smith said in the Matrix films, "It's all about me..." (although technically the line is "Me, me, me; it's all about me.") But I see this a lot when it's first person point of view. One sentence after another starts out with "I." You've got to mix it up; start with a verb: "Slumping at the table, I..."
or an adverb: "Angry at her unfair accusation, I..." or an adjective: "Mottled skin covered my...." or whatever else. Just glance down the page and circle all the I's. Because sometimes, your I's frighten me.
3. You can't speak for me--or anyone else because your quotes are lost in text. If one character is in the spotlight, saying or doing something, you must start a new paragraph when the speaker changes. If not, this creates confusion over who was speaking (and a dense text). For example: "I don't like you!" she screamed. I cringed at the harshness of her voice. "What did I do to you?" It should be like this:
"I don't like you!" she screamed. NEXT LINE: I cringed at the harshness of her voice. "What did I do to you?" Not only does it separate the two characters by action and words, it clarifies the dialogue because the "What did I do to you?" is clearly identified with the first person POV, not the initial character.
4. Repeat. Repeat. Repeat. Okay, so you're describing something, let's say a road. You DO NOT need to keep saying "the road." Substitute the pronoun "it." See: "The road stretched lazily before me, winding down, luring me into the coolness of the woods beyond. It was hard packed dirt, and no tire tracks were visible, giving evidence of previous travelers. I wondered how many people had traveled this way, only to meet their doom." Now I could have said "the road" in all three sentences, but by using the pronoun "it" and the phrase "traveled this way" I didn't have to repeat myself and bore you. If you can't think of another word (thesaurus, where art thou?) then vary the sentence structure: start with a verb, an adjective, an emotion, something other than "the road." Do I need to repeat myself?
5. "A foolish consistency is the hobgoblin of little minds," said Ralph Waldo Emerson. If you follow the same pattern of subject, verb, predicate sentence after sentence, Ralph is talking to you. Follow this: "Greta slowed down the car. Barry hopped in. Carrie asked them who had the tickets.Greta answered she did and drove to the concert." The sentences, even the last one which is more complex, all start the same way. This is a variation of the I, I, I, only now it's infecting the other characters' actions. Don't always start with the subject, do a change up, pull a surprise. And just because you throw some dialogue in between doesn't mean you've spiced things up. If every paragraph following dialogue follows with the subject/verb pattern, you're boring your readers and not progressing your writing skills.
Do famous authors do this? Why, yes, and they get away with it. But they're famous for some reason and you're not. And you don't want to be in the company of low skilled writers. Give your manuscript a good perusal and see not if, but how many times you have fallen into these bad habits. Now I have to go check my manuscript because I know I've violated all these rules somewhere. Happy searching/revising!