- When in doubt, follow the guidelines for the publication/publisher to which you're submitting. See? That wasn't so hard! If the editor at Fantastic Stories of Furry Bondage insists on triple-spaced manuscripts in Arial 14pt with 0.8" margins, so be it. Because...
- One of the purposes of computers is to automate mindless repetitive tasks like formatting. Your market wants underlines instead of italics? A global search-and-replace will do the trick. Same for two spaces after a period (versus one space), proportional fonts (such as the inexcusable Times New Roman, Arial/Helvetica/Univers, Bookman, Century Schoolbook, etc.) versus monospaced (such as the barely excusable Courier, Andale Mono/Consolas, Prestige, and other fonts that look like they came off a manual typewriter), and other minutiae that authors spend waaaaaaay too much time worrying about when they should be asking "Is my writing crap?"
- Aside on computers: Never, never, never send a document as an attachment in a proprietary format. Send it, instead, as either plain text (if appropriate) or RTF (if formatting matters at all). You cannot know in advance whether the machine at the other end even shares your operating system, let alone version of software... and given the continued pathetic attachment of the graphic arts community to Cupertino toys, there's a decent chance of a translation error. Just try translating "smart quotes" between Macintosh and Windows word processors... especially if the file has ever been edited by either WordPerfect or any of the "free with the machine" word processors shipped on lower-end Macs...
- Just about the only universal rule of manuscript submission is to print on only one side of the page, in black ink, using a serifed Roman (that is, upright and non-connected) typeface for the body of the text. Different markets and purposes have vastly different formats for manuscript submissions, and they continue to evolve. For example, Jay's piece includes a quote from Dr Stan Schmidt, the editor of the science fiction periodical Analog, claiming that "Computers also make it easy to do actual italics instead of underlining, but most [editors] would rather you didn't, and continue underlining instead." As Dr Schmidt, a physicist, should be all too aware, that's true only within certain boundary conditions — most editors of commercial-category fiction, and perhaps then only for shorter works. Anyone who submits book-length serious nonfiction these days had bloody well better be using italics, and using them correctly; "most" editors in that segment of the publishing industry prefer italics, because they mean something different than they do in fiction. As an example of just how strange things can get, consider this fairly vanilla law journal submission format (you'll have to download the PDF) — it's not even double-spaced!
- Follow the appropriate documentation conventions. That may seem like a surprising consideration to fiction writers, but the success of Jonathan Strange and Mr Norrell should give even you pause. Question: Were the footnotes submitted as footnotes; as endnotes; or in some other fashion? (Hint: It was written and first submitted in England, so the answer is... readily apparent only to those of us whose perception of publishing doesn't stop at the edge of the Pond.) There are style guides for each of the major areas of publishing, and remember to check the publisher's guidelines.
Of course, I could have said all of this on Jay's own LiveJournal page if commenting didn't require a LiveJournal "account." And that's a subject for another time... except to note that I don't have one, I won't be getting one any time soon, and phhhhhhhht to those who think it an absolute necessity.