The Top 20 Common Errors Checklist
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Sometimes you get a sentence back with a red mark, sometimes a green squiggle from the computer, and sometimes just a feeling that something is off — but you cannot say what. This is the scan-and-fix list for exactly those moments. Twenty of the most common slips, each with the symptom you would notice and the quick fix beside it. Run your eye down it, find yours, fix it, move on.
It is not a test and there is nothing to memorise — think of it as a final safety check before you hand something in. Read your writing through once with this list open, and most of the marks that would have come back in red get caught before anyone else sees them. When a slip keeps catching you out, follow the link to the article that teaches it properly — a good place to start is The Walk-In Clinic, which matches a symptom to its fix.
| # | Symptom (what you wrote) | Fix |
|---|---|---|
| 1 | its / it's muddled | it's = it is; its = belonging to it. Test: can you say "it is"? See Its / It's, Their / There. |
| 2 | their / there / they're | their = belonging; there = place; they're = they are. |
| 3 | your / you're | you're = you are; your = belonging to you. |
| 4 | me and Sam went… | Cover the other person: I went → Sam and I went. See Me and Him. |
| 5 | between you and I | After a preposition, use me: between you and me. |
| 6 | should of | It is should have (the sound of should've), never should of. |
| 7 | everyone are | Everyone takes a singular verb: everyone is. |
| 8 | the team are/is wobble | Group words can take is (safe) or are — just be consistent. |
| 9 | A comma splicing two sentences | Two full sentences need a full stop, semicolon, or joining word — not just a comma. |
| 10 | A run-on (no punctuation between ideas) | Break it into sentences, or join with and / but / because. |
| 11 | A fragment (a piece, not a sentence) | Give it a subject and a verb, or attach it to the sentence beside it. |
| 12 | apostrophe's on plurals | Plurals take no apostrophe: two dogs, not two dog's. |
| 13 | could care less | You couldn't care less (you have none to lose). |
| 14 | alot | Two words: a lot. |
| 15 | definately | Definitely — no a. |
| 16 | affect / effect | Affect is usually the verb, effect the noun. |
| 17 | fewer / less | Fewer for things you count, less for amounts. |
| 18 | Dangling starter (Walking to school, the rain…) | Make sure the opener describes the real subject: Walking to school, I got soaked. |
| 19 | Wandering tense (past → present mid-story) | Pick one tense for the piece and hold it. |
| 20 | Capital letters missing or over-used | Capital for names and sentence starts; lowercase for ordinary nouns. |
Nobody is born knowing all twenty — you just meet them one at a time, and the ones you personally trip over become obvious fast. Keep this page open for a final read-through of anything important: an essay, a message that matters, a form. Fix the two or three that jump out, and let the clinic take you to the full explanation for the ones that keep turning up. It is not about being perfect — it is about catching the slips that a reader would notice before they do.
Where next
- Common Errors — the young-learner clinic — the bigger map this sits inside
- The Walk-In Clinic — start here: name your problem, find the fix
- Its / It's, Their / There, You're / Your — the apostrophe mix-ups
- Do I Get Marked Down for "Me and Him"? — pronoun case, sorted