If you use a dateline and send the story to media in advance, be sure to specify the time and date of release. Number each page. Staple all releases. Many writers prefer stapled releases to avoid misplaced pages on cluttered desks, and those that don't can easily separate the pages to work with them. This arrangement makes it easier for busy writers opening mounds of releases to understand the gist of the story quickly.
Mail releases well in advance.
In writing releases, don't editorialize. Just give the facts. Double-check facts, names, degrees, and dates. Tailor your mailing list. And it should be kept up to date by surveying recipients periodically via return postcards.