I was wondering do you ever write words of dialogue in all capitals letters? For example if one character yells at another to suddenly stop, would it be 'STOP!' or just 'Stop!'? Thanks.
. I'd use capitals in referring a STOP sign, but otherwise in speech it'd be lower case. Do you have any other context in mind?
Just "Stop!" I don't like the over-use of exclamation points. They should be used exceedingly sparingly. Feeling a sense of urgency to a degree that one has to shout "stop!" is one such circumstance where an exclamation point is appropriate. Adding all caps would be overkill.
Depends on who you're writing for. If it's a chapter book (which I take to be geared for children ages 8-10? I could be wrong) then I think all caps is ok if that's what you like. If it's a book for anyone older than 12, I would avoid all caps at all costs. Personally I hate all caps - I find them childish and irritating, like the author's just trying too damn hard and too insecure in her own writing abilities to trust that the strength of the dialogue would come through even without cheap tricks like that. Like I say, I understand the use of all caps for books for very young audiences. But for teens and adults, it's a definite no-no for me.
In all my searching of information on italics, I found the use of caps for emphasis frowned upon if it was mentioned at all.
Even in narrative description (unless you're writing down a traffic sign or something of the like), I'd suggest using lower-case letters in your writing. While it's used for shouting in text-like settings, you can use dialogue tags and environment much more efficiently in your novel. I've seen upper-case shouting in a book once, and that paragraph really grated my nerves. A few lines later, the author used the same tactic for emphasis - I mean, I'm no expert at this writing (and don't expect to be one before a millenium or so), but isn't that sort of the purpose of italics? Anyways. Keep to lower-case whenever possible is my advice.