Style rules look fussy until you have two writers producing the same page. One uses a serial comma, one does not. One writes 3pm, one writes 3:00 PM. Neither is wrong, and the combination looks careless.

The answer is not a 300-page manual. It is a short set of defaults that covers the cases that actually appear in your writing, agreed once and applied everywhere. Below are defaults that work for most small businesses, with the reasoning where it matters.

Punctuation: pick the common cases

Choose a position on four things and you will have covered most of it.

  • Serial comma: use it or do not, but decide. Using it avoids ambiguity in lists such as invoices, statements, and reports.
  • Dashes: pick one style for parenthetical asides, spaced en dash or unspaced em dash, and use it consistently.
  • Apostrophes: use curly apostrophes in body text if the CMS supports them, and fix the ones that arrive straight from a paste.
  • Quotation marks: British style usually puts punctuation outside unless it belongs to the quote. American style puts commas and full stops inside.

Keep the rules to what a reader might notice. Nobody has ever abandoned a page because the dashes were en rather than em, but a page mixing both looks unedited.

Numbers: digits for scanning

The old rule of spelling out numbers under ten and using digits above is a reasonable default, with exceptions that matter more than the rule.

Always use digits for prices, measurements, percentages, statistics, times, and anything a reader might compare. Always spell out a number that starts a sentence, or rewrite the sentence. Use digits in tables and headings, where scanning matters more than prose rhythm.

For ranges, use the shortest unambiguous form: 10–15, 2019–2024, 15–20kg. Decide whether to close up units or add a space, and apply it to every measurement on the site.

Capitalisation: fewer capitals, fewer arguments

Sentence case for headings is easier to maintain than title case, because there is no debate about whether of counts as a word to capitalise. It also reads more naturally in a list of headings.

Job titles are lowercase unless they sit directly before a name. Product names follow the spelling in the brand guide, and that spelling does not change mid-sentence. Seasons, directions, and departments are lowercase unless they are part of a proper name.

Pick one form for the company name and never deviate, including in email signatures and page footers. The most common inconsistency on small business sites is the company's own name.

Most style decisions are not about correctness. They are about removing a choice that nobody needs to make twice.

Dates and times

Choose one format and use it in prose, tables, and metadata. Twelve March 2026 and 12 March 2026 are both clear; 12/03/26 is not, because half your readers will read it as December.

For times, write 9am, 2.30pm, or 14:30, and state the timezone wherever a reader might be elsewhere. Use a consistent separator between hours and minutes, and avoid both forms on the same page.

Abbreviations and acronyms

Spell out an abbreviation on first use unless the audience uses it daily. VAT, SEO, and API may need no explanation for your readers; internal project codes almost always do.

Do not add full stops to abbreviations that are written without them in common use. Do not invent plurals with apostrophes: APIs, not API's. Keep a short list of approved abbreviations in the guide, and a list of banned ones that have caused confusion.

Currency and units

Decide whether to write £1,200 or GBP 1,200, and whether prices include tax. State the currency once in a table header rather than repeating the symbol in every cell.

Use the measurement system your customers use, and convert where the audience is mixed. A single unit error in a specification is the kind of mistake that ends up in a returns conversation.

Know where to stop

A style guide is not a grammar course. If a rule does not change how the page reads, or does not resolve a disagreement that keeps recurring, leave it out. The document should fit on two pages and be searchable in under a minute.

Name a reference for anything the guide does not cover, and let the editor decide the rest. The goal is a page that looks like one team wrote it, not a page that satisfies a copy editor's entire worldview.

  • Serial comma decided
  • One dash style
  • Number style for prose and tables
  • Sentence case for headings
  • Company and product names fixed
  • One date format, one time format
  • Abbreviations list agreed
  • Currency and units stated

Write the rules down, apply them to the templates, and review once a year. Consistency is a small pleasure for the reader and a large saving for the team.