(adapted from Godfrey, P. M. Type and Content, Aldus Magazine, Sept/Oct, 1994. p. 51-58.)

Boldface is commonly used in headings. In textbooks, reference works, and instructional material, a new term being introduced or explained may be set in bold. In general copy, boldface should not be used for emphasis.

The way to emphasize a word is to italicize it. (Even so, skillful writers keep the device to a minimum, preferring to make the desired emphasis plain by the structure of the sentence itself.) Most typewriters could not produce italics, so underlining was used instead. With a computer, you use italics for emphasis.

One important and often ignored use is to italicize a word used as a word ("The term font is much misused."). Foreign words not yet naturalized in English are customarily italicized. So too are the titles of independent works of art, such as books, newspapers, magazines, operas, plays, motion pictures, paintings, and statues. (Titles of shorter works and of parts of larger works, such as songs, arias, chapters, or articles, are enclosed in quotation marks.) The names of the parties in a lawsuit are also italicized (Gibbons vs. Ogden), as are the scientific names of genera and species (Felis domestica, Rosa hugonis).

Small capitals are conventionally used for A.M., P.M., B.C., and A.D. Some publications have also started using them for acronyms. That seems a good idea. If acronyms, which are pronounced as words (such as NATO and RAM), are set in small caps, and initialisms, which are pronounced letter by letter (such as AFL-CIO and CPU), are set in full caps, readers unfamiliar with a given one would know at a glance how to say it. However, unlike the other typographic conventions, this practice is not in wide enough use to be considered a standard.

The three short horizontal lines in common use are the

• - hyphen
• — em dash
• – en dash

A hyphen is used to break a word at the end of a line; to connect two words that jointly modify another (short-lived phenomenon, three-foot board); and in certain compound words (mother-in-law, ne'er do-well, forget-me-not).

The em dash is what most people mean by "a dash." (The typist's expedient of two hyphens for a dash should never appear in typeset material.) The common use of an em dash is to indicate a break in thought or in the structure of a sentence (We could—oh never mind) and to set off an aside or parenthetical element (The governor was he a knave or a fool?—professed to know nothing about the matter), where it functions like the comma pair and the parentheses, and is intermediate in strength between them.

The en dash, is longer than a hyphen but shorter than an em dash. The standard use of the en dash is between numbers (beat the Giants, 5–3; reigned 1066–87; pages 88–92). It also is useful when one wants to connect two "words," and one or both are themselves two words or hyphenated (the Chicago–New York route; of English–Scots–Irish parentage; anti–blood–clotting agents; Teddy bear–like; the Free Trade–Protectionist controversy).

Traditionally, a paragraph is indented from the left margin by a space the width of the capital letter M in the font in use; an em space. A new paragraph is always signaled in some way, usually by indenting its first line from the left margin or, if the first lines of paragraphs are to be set flush left, by adding space between paragraphs. Without one of these signals (or both, but that is usually unnecessary), when a sentence and a line end together at the right margin, the reader cannot be sure whether the next sentence begins a new paragraph.

Using genuine quotation marks is another essential to producing typeset-quality materials. Look at the quotation marks and apostrophes in any well-produced book or magazine, and you'll see they're curved and widen at either the top (the apostrophe and close-quotation marks) or the bottom (the open-quotation marks). With modern software and printers, it's quite possible to produce true, or "curly," quotation marks and apostrophes.

Diacritical marks, or accents, are integral to many languages, and even appear in a few foreign words now commonly used in English (café, résumé, façade). Most word processing systems support the use of accents.

There is a long-established convention that headings are not capitalized like ordinary text. Which words have initial caps in heads is decided neither arbitrarily nor according to aesthetic considerations, but according to what part of speech the word is. If you don't know a noun from a conjunction, your best bet is to disregard the convention altogether and capitalize heads like ordinary sentences, an increasingly common practice.

Headings are traditionally referred to a A-heads, B-heads, C-heads, and so on, in descending levels of importance.The appearance of a head should make it absolutely clear to the reader whether it is an A- head, a B-head, or a C-head. To most readers, bold signifies more importance than light, all caps more importance than upper and lower, and larger type more importance than smaller. In choosing the type for heads, therefore, keep all three of these characteristics in sync.

One expedient, if you find you need an additional level of head and don't want to mix typefaces, is to add the caps-and-small-caps combination in the same face. A head in caps and small caps would be obviously intermediate in level between one in solid caps and one in upper and lower.

Don't stack more than two heads together without intervening text. (Real purists don't like the look of even two heads together.)

Several things done on the typewriter are definite faux pas on a computer. Besides two hyphens for a dash and underlining for italics, typing two spaces after a period at the end of a sentence is another hangover. Type one space between sentences.