Using punctuation points properly

Did you ever stop! to consider: just how much? punctuation marks – all of them – brighten; enliven; and pep up our translated texts? And how quickly incorrect punctuation can undermine your good name on the market?.
From the attention-grabbing exclamation point to the incredulous question mark, extending through a generous range of dashes, dots and commas in assorted configurations, punctuation is a secret weapon that can turn your professional translation from boring to brilliant (together with a couple of other tricks like alliteration, abbreviation, reiteration, rhyme and portmanteaux, all addressed in another article).
All those pesky punctuation points are actually signposts that underscore meaning, deepen or lighten tone and spotlight key points. However, their use varies from language to language (and even from decade to decade, after the advent of the Internet), with many pitfalls that can baffle even experienced translators.

A disclaimer here: I refer only to English, which is my specialized sphere of expertise.
Although there are fourteen punctuation marks commonly found in most Western European Languages, their specific usage varies widely, to the extent of indicating different meanings.
The dot, period or full stop (for the Brits), question mark, exclamation point and ellipsis often indicate the end of a sentence and its tone; the hyphen joins two words together (less popular since the advent of Internet); commas indicate a breathing space in a longer sentence; and a semicolon (or a dash) precedes an explanation, or a list or an enumeration with semicolons after each item (except in UN documents). Apostrophes indicate possession (Jim’s dog) or somewhat casual abbreviations (don’t, let’s) that should be used only for informal documents or direct speech, never indicating a plural noun (1980s, not 1980’s).

Paired punctuation signs are used to distinguish shorter phrases within a longer sentence, often inserted almost as an aside, which can be removed without affecting the basic structure of the expression. Double quotation marks are for direct speech, with the final punctuation point before the closing quotation mark (“Let’s go!” he said). Single quotation marks are an elegant way of distinguishing citations from books or speeches.
Brackets form an entire family of pairs: parentheses or round brackets are the most common in ordinary texts. Square brackets or box brackets are commonly used in international treaties to indicate alternative wording and are removed in the final document. Personally, I use them around the word sic to indicate what I believe is a typo in the original text I cannot correct – like 20% (ten per cent) [sic] – and also when I need to insert a [Translators Note: … ] in a file. Braces or curly / squiggly brackets seem to be limited to mathematical equations, in my experience.

A single dash can replace or follow a colon to indicate a list, while paired dashes can highlight a phrase more effectively than brackets, I feel.
The two ugly sisters of the punctuation family that have surely earned a position in the translation services world are the asterisk, tagging a brief explanation that does not fit into the flow of the text without adding an extra footnote (translators should avoid this at all costs), and the front slash, for indicating an alternative when the source word is ambiguous (joggers/runners).
Hope this helps you all smooth out the flow of your translations into English.