Disambiguation pages are not encyclopedia articles – they are navigation aids!
Users arrive at these pages with a specific article in mind. So when you edit these pages:
DO:
Green check.png Limit descriptions to what's necessary.
Green check.png Put the link at the start of each entry.[a]
Green check.png Sort entries; group by subject if necessary.
Green check.png Put the primary topic at the top, if one exists.
Green check.png Use {{Wiktionary}} for dictionary definitions.[b]
Green check.png Fix incoming links to target the intended page.
Green check.png Tag pages that need work with {{dab cleanup}}.
DON'T:
Red x.svg Don't include entries without a blue link.
Red x.svg Don't include red links unless used in articles.[c]
Red x.svg Don't include multiple blue links in an entry.
Red x.svg Don't include references or external links.
Red x.svg Don't list dictionary definitions.[b]
Red x.svg Don't list every article containing the title.
Red x.svg Don't pipe links except to format.[a]

Also:

Do consider joining WikiProject Disambiguation.

Notes

  1. ^ a b Unless the linked article is not the ambiguous item itself, but part of the description.
  2. ^ a b Put the wiktionary template at the top of the page to provide a link to dictionary definitions.
  3. ^ To see if a link is used in existing articles, click it, then click the "What links here" tool. An entry with a red link must include a blue link mentioning the term.

See also