Repetition- Best to avoid as much as possible.
Spelling- Spelling is super important to the flow of a story in terms of appearance.
Grammar- Equally as important as spelling, it keeps things accurate in terms of usage to words.
Plot- A plot has to connect. It can be general, such as a murder case. Finding out who killed who, why, with what, and when. Or it can be subtle, like.. spotting a bracelet on a dead woman you stumble upon.. and then when you arrive at the cop station and you see that same bracelet on another woman.. In the sense of the bracelets, it could mean like.. a man's victims are women with that particular bracelet. Get what I'm saying? Or it can be very common, such as following a plan from A to Z, if that makes any sense.
Punctuation- Without this you have run-ons! They are kinda bad. We do not want one long sentence that makes literally no sense because all the words are connecting with no punctuation. You also need it for contractions like don't, haven't, you're, etc. Some also use ' for a character's thoughts. And the most common is " for talking.. and .'s for a sentence ending. Don't forget ,'s. They are also very important.
Realistic/Fantasy- What I mean when I say "realistic/fantasy" is basically like.. Try to make things believable. Like.. say two of your characters are walking towards each other. They are about a football field's length away from each other. Suddenly, the guy on the left is squashed by a stadium-stand (those bench things that are typically found at games like football and whatnot). Ok, first off.. how did he get squashed? How did the stand suddenly get from destination A to B. To be better, the guy on the right could have used some crazy powers like object manipulation (something like the Force, for example) and lifted the stand and moved it over the guy on the left and then dropped it on him. You got to have details. They are important.