[found on thepunctuationguide.com]
. . .
“An ellipsis is a set of three periods ( . . . ) indicating an omission. Each period should have a single space on either side, except when adjacent to a quotation mark, in which case there should be no space.”
Notwithstanding its versatility, the em dash is best limited to two appearances per sentence. Otherwise, confusion rather than clarity is likely to result.
“The most flagrant way a writer demonstrates contempt for his readers is by ignoring punctuation altogether. A close second is the abundant use of the exclamation point. Some writers even use three or more exclamation points, lest the reader not fully grasp the significance of what is being said. To be effective, the exclamation point should be used in moderation.”