Most Common Errors
| Error | Wrong | Right | Rule |
|---|
| Their/There/They're | Their going to the store. | They're going to the store. | They're = they are. Their = possessive. There = location. |
| Your/You're | Your welcome. | You're welcome. | You're = you are. Your = possessive. |
| Its/It's | Its a beautiful day. | It's a beautiful day. | It's = it is. Its = possessive (no apostrophe). |
| Affect/Effect | It will effect sales. | It will affect sales. | Affect = verb (influence). Effect = noun (result). |
| Then/Than | More then enough. | More than enough. | Then = time. Than = comparison. |
| Lose/Loose | Don't loose the file. | Don't lose the file. | Lose = misplace. Loose = not tight. |
Punctuation Quick Reference
| Item | Description |
|---|
Oxford Comma | Comma before 'and' in list. 'Apples, bananas, and oranges.' AP says no. Chicago says yes. Be consistent. |
Semicolon | Connects related independent clauses. 'The build failed; we need to fix the tests.' |
Em Dash (—) | Strong break — like this — in a sentence. No spaces (AP style) or thin spaces (Chicago). |
En Dash (–) | Ranges: 'Pages 10–20'. Compound adjectives: 'New York–London flight.' |
Hyphen | Compound modifiers before noun: 'well-known author.' No hyphen after noun: 'The author is well known.' |
Apostrophe | Possessive: 'user's data' (singular), 'users' data' (plural). NOT for plurals: 'CPU's' → 'CPUs.' |
Style Guide Differences
| Rule | AP Style | Chicago Style | Tech Writing |
|---|
| Oxford Comma | No | Yes | Yes (clarity for technical lists) |
| Numbers | Spell out 1-9, numerals 10+ | Spell out 1-99, numerals 100+ | Numerals for all values in docs |
| % | Use % sign | Spell out 'percent' | % sign (save space, scannable) |
| Titles | Quote marks: 'The Raven' | Italics: The Raven | Italics or code formatting for technical terms |
| Emails | No hyphen: email | Hyphen: e-mail | No hyphen (industry standard) |
Quick Fixes
| Item | Description |
|---|
Passive Voice | 'Mistakes were made' → 'We made mistakes.' Active = clearer, more accountable. |
Sentence Length | >30 words = likely too long. Split or restructure. Average 15-20 words for readability. |
'That' vs 'Which' | 'That' for essential: 'The API that returns users.' 'Which' for non-essential: 'The API, which is new, returns users.' |
Parallel Structure | Wrong: 'She likes hiking, to swim, and bikes.' Right: 'She likes hiking, swimming, and biking.' |
Dangling Modifier | 'Walking down the street, the trees were beautiful.' → 'Walking down the street, I saw beautiful trees.' |
Pro Tip: Read your writing aloud. Your ear catches errors your eyes miss — awkward phrasing, run-on sentences, missing words. This single habit catches 80% of common errors.