In the course of critiquing more than eight hundred stories, I've found myself often mentioning four major writing issues: frequency, echoes, redundancy and repetition. Moreover, it has become clear how often my own stories suffer from the same obstacles to clean, clear, concise and succinct writing.
Frequency refers to specific words, types of speech, and/or phrases a writer uses repeatedly. Some common ones are "just", "so", "as", "that", "then", "glance" and "smile". Sometimes it is a phrase, such as "in fact" or even in a dialogue tag, such as "(s)he told him/her". Similar problems come with the overuse of modifiers, such as adverbs ("-ly"). My own personal nemesis is the reoccurrence of filter words, such as "thought", "wondered", "remembered" and "realized". Recently I've been surprised by the overuse of "up" in phrases: "stood up", "hold up", "picked up", and "straightened up". This is probably a product of how our everyday language is changing, but we writers know speech is not dialogue or narrative.
Running a story through a word/phrase counter is an easy remedy and can be useful when used in conjunction with the search function of your word processor (http://www.writewords.org.uk/word_count.asp). Frequency statistics are also available in CC's Novel System, as part of writing programs (such as Scrivener) or editing software (https://prowritingaid.com/) . Remember, you may not want/need to edit every occurrence. Consider the context and what sounds right for your work.
Echoes are closely related to frequency in that it refers to the same word appearing in close proximity to a reappearance of the same word. (See the echoes?) Of course, frequency and echoes often occur accidentally when we writers are fast drafting and need to get the ideas down on paper. You might want to try highlighting the second (or third?) usage to make sure you can reassess during the revision/editing phase.
Redundancy involves the usage of words that can be deleted without losing meaning. For example: "Tom picked up the orb from the table with his hands." Unless Tom is a special type of entity, the reader will assume he used his hands and deleting the phrase will not adversely affect the reader's interpretation. Of course, if Tom is a six-legged, four-handed, eight-foot beetle, all bets are off.
While repetition may seem to have the same meaning as frequency, that is not how it is being used here. The most common forms of repetition I have found have more to do with concepts, ideas, actions and basic information. Once the reader knows the character has blonde hair, there is no need to repeatedly refer to "honey-blonde", "golden locks" or "sun-kissed tresses". As with all things writing-related, there are times repetition, echoes and redundancy is not only good, but necessary. When the "sun-burst tattoo on her upper right arm" is a passing hint in the first description, it may be imperative to remind the reader when it shows she's related to the villain about to kill your hero.
Of course, critters are especially useful in locating the words or phrases marring the readability of your story. We haven't read it before and can often spot that unneeded instance. Reading your work, exactly as it is written, or having someone else read it to you are other possible solutions.
These four oversights can lead to similar sentence structure, slow pace and flow, infringe with readability and ultimately contribute to reader boredom. While none of them are "wrong", increased awareness may change your story from good to great.