Okay I'm talking about emails here as nowadays that's pretty much the only way to communicate especially for anything long distance or as an request to make an appointment. So I was in this situation quite a few times (probably partly fault on me for not always sure of email etiquette...): I sent an email asking for something (non-coursework related questions, advice, etc) and just simply did not get an answer at all and weeks has elapsed...
What would you recommend doing if:
1) I do not know the person on the other end of the email
2) I DO know the person, and have talked to them in person before (and not a bad conversation, I think!) and, as far as I know, nothing terrible happened since I last talked to him/her.
3) Same in case 2), except that I did not get responses for more than one different questions asked over different emails sent probably a week or two more apart.
And two related questions:
4) How can I find out whether I'm asking too much, or asking something unreasonable, or asking in a really bad way? (I'm looking for maybe some examples of good and bad request emails sent to professors)
5) Do professors in general prefer in person meeting over response over email? My schedule is usually a nuisance to schedule around, so I tend to ask things (including recommendation) over email than asking for an appointment. Is this not good?
I heard anecdotes on professors ignoring emails from people they don't like for whatever reason (one guy I know told me that his email had been ignored because the professor thought he was the very annoying kid at the class the professor taught; the professor realizes his mistake later). What is a polite way re-send an email to in case that the professor is just busy or has overlooked my email?