There are reportedly fourteen punctuation marks. Unfortunately, the lists I consulted do not completely agree. Some include “braces” while others list a “slash.” With consensus on the other thirteen, that makes a possible total of fifteen punctuation marks. Here are my thoughts on all fifteen:
Comma: I use them, more then I should, and always before “and” when three of more items are in a list.
Period: I used to be compelled to place two spaces after periods at the end of sentences, but not anymore; I retrained myself. When not ending a sentence, I tend to leave them out, as in PhD.
Question mark: I question if this sentence needs a question mark? (not really, but I do occasionally stumble over this)
Exclamation point: Except for here, I never use them in groups!!! I do, however, tend to overuse them, especially in emails!
Quote: Except for colons and semi-colons, all punctuation goes inside quotes—usually.
Colon: The use of colons is more art than science. I pop them in when it feels right and my proofreader fixes them.
Semi-colon: I am in love with semi-colons; I tend to overuse them; it sometimes borders on the ridiculous.
Apostrophe: Many novice writers use them when they aren’t warranted or omit them when they are. It’s and its are common stumbling blocks.
Hyphen: My tendency is to insert them where a space is needed or to remove them (without adding a space) where they are required. I think I am just ahead of my time.
Dash: I may use dashes too much—but I always use the en-dash, while dismissing the em-dash.
Ellipsis: This is a great tool when writing dialogue or making sense of a wordy quote, but other uses strike me as sloppy writing.
Parentheses: I tend to add parenthetical sentences (and thoughts) way too often.
Brackets: This is a great device to insert editorial comments. [Other than that, I know of no other use.]
Braces: Braces are lovely in appearance and elegant in design, yet I can recall no time when I have ever used them.
Slash: I’m not sure if there is a proper place to use a slash, but I often see it (and occasionally use it) when connecting two thoughts or words by inserting “and/or” between them.