17 very simple tips to improve the content of your web page

1. Help the reader to SCAN your content
   People read differently on the web than they do on paper. They scan for clues to see what the page is about, to know if the information they want is there. Help them out by using headings, bullet points, hyperlinks and bolded keywords.
2. Put the most important info first
   Give prominence to what your users want most. That's your most valuable content. The remaining information should follow in descending order of importance.
3. Outcome, not process
   No need for welcome messages, scene-setting or historical background. Don’t explain the process, just give readers the outcome.
4. Be informal, be direct
   Writing on the web is more conversational than the administrative style used in typical Commission writing. You can say "you" if it helps the reader understand what action to take
5. Think like a googler
   Write from the user’s perspective (not the Commission’s), with the words they use when they search the internet.
6. 1 paragraph = 1 idea
   Each paragraph should have just 1 main idea.
7. Use bullet points
   They help users scan. Don't use a colon before the list, don't use punctuation at the end of each point and don't capitalise the first letter of each point. 
8. Keep sentences short
   Split sentences longer than 25 words.
9. Get good at using headings
   They help people scan the page. People often click away without reading your content if the headings aren't clear and relevant.
10. Keep formatting to a minimum
    Bolding is used to emphasise key ideas. But ask yourself – with your short, focused paragraphs and your clear headings, do you really need to use bold type as well?
    Don't use italics, and don't underline.
11. Don't use jargon and keep it simple
    When using jargon, take into account that users outside of the institutions may not be familiar with certain terms. See the A to Z list for common EU jargon and alternatives, and the A to Z list of complicated words and phrases and more-accessible alternatives.
    Keep your writing simple. Don't say "employment opportunities". Do say "jobs".
12. Use the active voice
    Has the application process been simplified by the committee? Or did the committee simplify the application process?
13. Tell the user what's behind the hyperlink
    Hyperlinks catch the eye as people scan the page. Use them to let the user know where they will end up when they click. Don’t use generic labels such as click here, here, more or read more. Don’t use URLs. Instead, use keywords. It’s okay if your link label doesn't match the title of the page you’re linking to as long as it describes the content clearly.
14. Don't capitalise (much)
    Avoid overuse of capitals, especially for things like documents, laws, policy areas, programmes, events. Use only for proper nouns (people's names and place names).
15. Follow the policy for dates, numbers, symbols 
    Dates are written like this: 29 October 2014. Do not write numbers out; use numerals instead (1, 2, 3, etc.). Decimals should appear like this: 9.7 billion people. Don't use the ampersand (&), monetary values are presented using their monetary symbol: €150, and the percentage symbol is fine, fine, fine (%).
16. Explain abbreviations (ABBR) once
    Write out the long form of an acronym or abbreviation the first time it appears in a text, followed by the short form in brackets.
17. Follow British English spelling conventions
    Prioritise British spelling over Americanization.

Source: https://webgate.ec.europa.eu/fpfis/wikis/pages/viewpage.action?spaceKey=WEBRAT&title=Quick+web+writing+checklist (login required)