12 Grammar Mistakes That Make Self-Published Books Look Amateur

These are the grammar and usage mistakes editors find most often in self-published manuscripts — and the ones readers mention in negative reviews. Here's how to catch them.

Readers forgive a lot — a slow chapter, a predictable twist, even a cliché or two. What they don't forgive is a book full of grammar errors. Reviews that mention "typos throughout" or "needed an editor" suppress sales for years, and they're among the most common criticisms in one- and two-star reviews of self-published books.

The good news: most grammar errors in self-published books fall into a surprisingly small set of recurring patterns. Learn to spot these twelve, and you'll catch the majority of the mistakes that make books look amateur.

1. Inconsistent Verb Tense

The most common structural grammar error in fiction manuscripts. Your book should be written in either past tense ("She walked to the door") or present tense ("She walks to the door") — and stay there. Tense drift usually happens in action scenes and emotional moments, where authors unconsciously slip into present tense for immediacy.

How to catch it: Read your most intense scenes separately, watching only the verbs. Tense slips cluster where the writing energy is highest.

2. Homophone Confusion

Spell check won't save you here, because both spellings are valid words:

  • their / there / they're
  • its / it's
  • your / you're
  • affect / effect
  • peek / peak / pique
  • lead / led
  • complement / compliment

How to catch it: Use Find to search for each of your personal problem words individually. Most authors consistently confuse the same two or three pairs — learn yours.

3. Lay vs. Lie

The error editors report seeing most often, and one that even bestselling authors get wrong. The short version: lay takes an object ("She lays the book down"), lie doesn't ("She lies down"). The past tense of lie is lay — which is why everyone gets confused.

How to catch it: Search for every instance of lay, laid, lie, and lying. Check each one against the rule. There usually aren't many, so this takes ten minutes.

4. Comma Splices

Joining two complete sentences with only a comma: "She opened the door, the room was empty." Either use a period, a semicolon, or a conjunction: "She opened the door. The room was empty."

Comma splices are sometimes used deliberately for pacing in fiction — but if you're doing it on purpose, it should look consistent and intentional, not scattered randomly.

5. Sentence Fragments (The Unintentional Kind)

Fragments are incomplete sentences: "Because she knew the truth." Fiction uses intentional fragments constantly for rhythm and emphasis. The problem is unintentional fragments — usually caused by editing a sentence and leaving half of it behind.

How to catch it: Reading aloud exposes unintentional fragments immediately. Intentional fragments sound punchy; accidental ones sound broken.

6. Dangling Modifiers

An opening phrase that doesn't attach to the right subject: "Running for the bus, her phone fell out of her pocket." As written, the phone was running for the bus. Fix: "Running for the bus, she dropped her phone."

These are hard to self-catch because you know what you meant. Beta readers and editors spot them instantly.

7. Subject-Verb Agreement Slips

Usually correct in simple sentences, these break down when distance grows between subject and verb: "The box of letters and old photographs were in the attic." The subject is box (singular), so it should be was.

How to catch it: When you see a long noun phrase before a verb, strip it down to the core subject and check the verb against it.

8. Apostrophe Errors in Plurals and Possessives

  • Plurals never take apostrophes: "the Smiths," not "the Smith's"
  • Singular possessive: "the dog's bone"
  • Plural possessive: "the dogs' bones"
  • And its (possessive) has no apostrophe — it's always means "it is"

Apostrophe errors are highly visible to readers and disproportionately mentioned in reviews, because they appear in simple sentences where nothing else distracts from them.

9. Dialogue Punctuation Errors

The most common fiction-specific mechanical error set:

  • Commas before dialogue tags: "I'm leaving," she said. (Not: "I'm leaving." She said.)
  • Periods before action beats: "I'm leaving." She grabbed her coat. (The action beat is a separate sentence, not a tag.)
  • Punctuation goes inside the quotation marks in US English.

If you only master one section of this list, make it this one — dialogue punctuation errors repeat on nearly every page of a novel, so getting the pattern right fixes hundreds of instances at once.

10. Inconsistent Hyphenation and Capitalization

Is it e-mail or email? Toward or towards? Is your character's hometown "the city" or "the City"? Any of these choices can be correct — the error is switching between them. Inconsistency signals carelessness to readers even when they can't articulate what's bothering them.

How to catch it: Keep a style sheet — a running list of every choice you've made — and check your manuscript against it with Find.

11. Misplaced "Only"

"She only wanted to help him" technically means helping is the sole thing she wanted. "She wanted to help only him" means he's the sole person. Only modifies whatever immediately follows it, and most manuscripts place it earlier in the sentence than intended. Readers usually understand from context — but precise placement makes prose noticeably sharper.

12. The Errors You Can No Longer See

The final category isn't a specific mistake — it's the phenomenon that makes all the others survive into published books. After reading your own manuscript ten or twenty times, your brain stops processing the words on the page and starts reciting what it knows should be there. This is why even professionally edited books ship with errors, and why authors who "read it five more times" keep missing the same typo on page 212.

The only reliable fixes are fresh eyes and changed conditions: time away from the manuscript, reading aloud, changing the font, printing it out — or having someone (or something) other than you check it.

How to Actually Catch All of This

A realistic error-catching sequence for a self-published book:

  1. Self-edit with the list above — targeted Find searches for your known problem patterns
  2. Run a grammar checker — Word's built-in checker or Grammarly will catch a first layer
  3. Read aloud (or use Word's Read Aloud) — catches fragments, tense drift, and awkward constructions software misses
  4. Get an external check — this is the step that catches what you've gone blind to

For that final step, a professional proofread runs around $0.02/word (roughly $1,600 for a novel). An AI-powered proofread from ScribeGlow costs $0.0004/word — about $32 for the same manuscript — and returns a .docx with every correction marked in Track Changes, so you can verify each fix yourself. For everything on this list, from homophones to dialogue punctuation to the typos your brain refuses to see, an external pass is what stands between your manuscript and the "needed an editor" review.

The Bottom Line

Grammar errors cluster into predictable patterns, which means they're catchable — with targeted searches, reading aloud, and at least one pass by eyes (human or AI) that aren't yours. Your story deserves readers who are immersed in it, not distracted by its mistakes.

Ready for a full error check on your manuscript? Try ScribeGlow free on your first 5,000 words — proofreading, line editing, or both, delivered as a .docx with Track Changes. No account required.