When I'm in my writing zone, I tend to slip into some bad habits, and often, I don't realize I'm doing them until I start editing and revising. Here are some of the big ones that writers often make.
Show; Don't Tell - We've all heard the command to show our readers without telling them what's going on. It is so easy to slip into this habit. Reread your chapters and eliminate sections that are just descriptions.
Every Little Detail - You don't need to account for every minute in your character's life. You can skip ahead in time and omit the routine details. For example, if your character if flying from New York to Nashville, and the airport and plane are not germane to the story, have her go to the airport and then jump ahead to the landing in Nashville. We don't need to know about the security check, inflight movie, snacks, or the baggage claim.
Cut the Chitchat - Dialog in fiction shouldn't contain the normal, mundane chatter. Pare down your character's conversations to what is needed for the story.
Keep it Conversational - Dialog in fiction should be conversational (unless there is a need to have a character be more formal). Use contractions, short sentences, or incomplete sentences to mimic how real people talk.
If You're Bored - If you're bored, your reader will be too. Cut the fluff. Get rid of unnecessary words and anything that slows the action of the story down.
Multiple Adjectives - Don't layer on the adjectives. One good one will do. And pick strong adjectives. Leave out the plain Jane ones that don't add anything to your sentences.
Weak Verbs - Look at your verbs. If they are weak or propped up by blah adverbs, rewrite the sentence. You need action verbs that will keep the momentum of the story.
Last Sentences - Look at the last paragraph of each chapter and verify that it compels the reader to continue on. If it's boring or slow, your reader will use it as a good stopping point.
Character Names - Avoid overusing your character's name. Look at your paragraphs. You shouldn't see the name over and over. If you find a pattern, rewrite some sentences. I've had beta readers tell me that the overuse of names slows down the action.
Overused Words - Know the words you tend to overuse. For some reason, I'll use a word or phrase multiple times. In my last manuscript, it was "peek" and "rolled his eyes." I searched for instances and did rewrites.
I tend to use "that" and "just" too much. During the revising stages, my search/replace feature is my friend. It helps me quickly find the overused words.
Exclamation Points - Don't go crazy with the exclamation points. Hardly anyone is that exuberant. My writer friend calls these the jazz hands of writing.
I find the writing is the easy part. The revising and editing take me much longer because I need to weed out the sloppy habits. Best wishes with your writing projects.