15 Common Writing Mistakes That Undermine Your Credibility

A single writing mistake can shatter your credibility faster than you can say "grammar." Whether you're crafting an important email, publishing a blog post, or submitting a proposal, these common errors signal carelessness to readers. Even worse? Most writers don't realize they're making them.

After analyzing thousands of documents, we've identified the mistakes that appear repeatedly across all types of professional writing. The good news: once you know what to look for, these errors become easy to spot and fix.

Grammar Mistakes That Make You Look Amateur

1. The Infamous Its/It's Confusion

This might be the most common mistake in professional writing. Here's the simple rule:

• It's = It is or It has (contraction)
• Its = Possessive form (belonging to it)

Wrong: The company updated it's privacy policy.

Right: The company updated its privacy policy.

Also right: It's important to read the updated policy.

Quick fix: Try replacing the word with "it is." If the sentence still makes sense, use "it's." Otherwise, use "its."

2. Subject-Verb Disagreement

Subjects and verbs must agree in number. Singular subjects need singular verbs; plural subjects need plural verbs. Sounds simple, but it gets tricky with complex sentences.

Wrong: The list of requirements are extensive.

Right: The list of requirements is extensive.

(The subject is "list," not "requirements")

Wrong: Each of the employees have submitted their reports.

Right: Each of the employees has submitted their report.

Quick fix: Identify the true subject by removing prepositional phrases. "The list [of requirements]" becomes "The list," which is clearly singular.

3. Dangling Modifiers

These occur when a descriptive phrase doesn't clearly connect to the word it's modifying, creating unintentionally hilarious sentences.

Wrong: After rotting in the basement for weeks, my brother threw out the potatoes.

(Was your brother rotting in the basement?)

Right: My brother threw out the potatoes that had been rotting in the basement for weeks.

Wrong: Walking down the street, the trees were beautiful.

Right: Walking down the street, I noticed the beautiful trees.

Quick fix: Make sure the subject performing the action immediately follows the introductory phrase.

4. Comma Splices

A comma splice happens when you join two complete sentences with just a comma. It's surprisingly common, it weakens your writing. (See what we did there?)

Wrong: The meeting starts at 10 AM, don't be late.

Right options:

• The meeting starts at 10 AM. Don't be late.
• The meeting starts at 10 AM, so don't be late.
• The meeting starts at 10 AM; don't be late.

Quick fix: If both parts could stand alone as sentences, you need more than a comma between them.

Style Mistakes That Weaken Your Writing

5. Passive Voice Overuse

Passive voice isn't always wrong, but overusing it makes writing feel weak and indirect.

Passive: The report was written by the team.

Active: The team wrote the report.

Passive: Mistakes were made.

Active: We made mistakes.

Sometimes passive voice works better, especially when the actor is unknown or unimportant: "The building was constructed in 1920." But default to active voice for stronger, clearer writing.

Quick fix: Look for "was/were + past participle" constructions. Ask "Who's doing the action?" and restructure with that actor as the subject.

6. Redundant Phrases

Why use more words when fewer will do? Redundant phrases clutter your writing and waste readers' time.

Common redundancies to eliminate:

• "Free gift" → gift
• "Advance planning" → planning
• "Past history" → history
• "Completely finished" → finished
• "Basic fundamentals" → fundamentals
• "In my personal opinion" → in my opinion
• "12 noon" → noon
• "Added bonus" → bonus

Quick fix: Question every adjective and adverb. Does it add meaning, or does it repeat what's already implied?

7. Nominalizations (Zombie Nouns)

Nominalizations occur when you turn verbs or adjectives into nouns, creating wordiness and removing action from sentences.

Nominalized: We need to make a decision about the implementation of the new system.

Direct: We need to decide how to implement the new system.

Nominalized: The committee will conduct an investigation into the matter.

Direct: The committee will investigate the matter.

Quick fix: Watch for words ending in -tion, -ment, -ance, or -ity. Can you replace them with their verb forms?

Clarity Mistakes That Confuse Readers

8. Unclear Pronoun References

When pronouns (he, she, it, they, this, that) don't clearly refer to a specific noun, readers get lost.

Unclear: When Sarah met Jennifer, she said she would handle the project.

(Who said what?)

Clear: When Sarah met Jennifer, Sarah said she would handle the project.

Unclear: The managers told the employees that they would need to work overtime.

Clear: The managers told the employees that the employees would need to work overtime.

Quick fix: When in doubt, repeat the noun instead of using a pronoun. Clarity beats elegance.

9. Misplaced Emphasis

Burying your main point in the middle of a paragraph or sentence weakens its impact.

Weak: There are several reasons, including cost overruns, delays, and poor planning, why the project failed.

Strong: The project failed for several reasons: cost overruns, delays, and poor planning.

Quick fix: Put important information at the beginning or end of sentences and paragraphs—these positions naturally draw attention.

10. Jargon and Buzzword Overload

Industry-specific language has its place, but overusing jargon alienates readers and obscures meaning.

Jargon-heavy: We need to leverage our core competencies to synergize cross-functional collaboration and optimize our value proposition.

Clear: We need to use our strengths to help teams work together better and improve what we offer customers.

Quick fix: Imagine explaining your point to someone outside your industry. Use the words you'd use with them.

Punctuation Mistakes That Disrupt Flow

11. Apostrophe Catastrophes

Beyond the its/it's issue, apostrophes cause countless problems.

Common mistakes:

• Plural vs. possessive: "The company's are merging" → "The companies are merging"
• Plural possessive: "The employees's lounge" → "The employees' lounge"
• Names ending in 's': Both "James's car" and "James' car" are acceptable—just be consistent

Quick fix: Apostrophes show possession or mark contractions. They almost never make plurals (exception: "Mind your p's and q's").

12. Hyphen Confusion

Hyphens connect compound modifiers before nouns but disappear after them.

Before noun: It's a well-known fact. She's a full-time employee.

After noun: The fact is well known. She works full time.

Exception: Don't hyphenate when the first word is an adverb ending in -ly: "highly skilled worker," not "highly-skilled worker."

Quick fix: If two words work together as a single adjective before a noun, hyphenate them.

13. Semicolon Misuse

Semicolons aren't fancy commas; they have specific uses.

Correct uses:

• Joining related independent clauses: "The project succeeded; everyone celebrated."
• Separating complex list items: "We have offices in Seattle, Washington; Portland, Oregon; and San Francisco, California."

Wrong: The team includes; developers, designers, and managers.

Right: The team includes developers, designers, and managers.

Quick fix: Both sides of a semicolon should be complete sentences (unless it's separating complex list items).

Word Choice Mistakes That Undermine Precision

14. Commonly Confused Words

English is full of similar-sounding words with different meanings. Here are the most frequently confused pairs:

• Affect/Effect: Affect is usually a verb (to influence); effect is usually a noun (a result)
• Then/Than: Then relates to time; than is for comparisons
• Lose/Loose: Lose means to misplace; loose means not tight
• Principal/Principle: Principal = main or head of school; principle = rule or belief
• Complement/Compliment: Complement = completes; compliment = praise
• Discrete/Discreet: Discrete = separate; discreet = careful/prudent

Quick fix: Create a personal list of words you often confuse. Check them every time you write.

15. Vague Quantifiers

Words like "many," "several," "a lot," and "few" leave readers guessing. Specific numbers or ranges provide clarity.

Vague: Many customers complained about the service.

Specific: Forty-seven customers complained about the service.

Alternative: Nearly 20% of customers complained about the service.

Vague: The process takes a while.

Specific: The process takes 3-5 business days.

Quick fix: Whenever possible, replace vague quantifiers with specific numbers, percentages, or ranges.

Your Action Plan for Error-Free Writing

The Multi-Pass Editing Method

Don't try to catch every mistake in one pass. Instead:

1. First pass: Focus on content and structure
2. Second pass: Check grammar and punctuation
3. Third pass: Refine word choice and style
4. Final pass: Read aloud to catch awkward phrasing

Build Your Personal Checklist

Everyone has writing weaknesses. Create a personalized checklist of your common mistakes. Review it before submitting any important document.

Use Tools Wisely

Grammar checkers catch obvious errors but miss context-dependent mistakes. Use them as a first line of defense, not your only defense.

Practice Deliberate Improvement

Pick one mistake from this list. Focus on eliminating it from your writing for one week. Once you've mastered it, move to the next. Small, consistent improvements lead to dramatic results.

The Bottom Line

Perfect writing doesn't exist, but professional writing should be clean, clear, and credible. These fifteen mistakes account for the vast majority of errors we see in professional documents. Master them, and your writing will stand out for all the right reasons.

Remember: every error you eliminate removes a barrier between your ideas and your readers. In professional communication, clarity equals credibility. Make every word count, and make it count correctly.